lunes, 5 de octubre de 2015

Instrucciones para médicos clínicos sobre el uso de RT-PCR y otros ensayos moleculares para el diagnóstico de infección por el virus de la influenza | Profesionales de la salud | Influenza estacional (gripe)

Instrucciones para médicos clínicos sobre el uso de RT-PCR y otros ensayos moleculares para el diagnóstico de infección por el virus de la influenza | Profesionales de la salud | Influenza estacional (gripe)



CDC. Centros para el Control y la Prevención de Enfermedades. CDC 24/7: Salvando vidas, protegiendo a las personas.



Instrucciones para médicos clínicos sobre el uso de RT-PCR y otros ensayos moleculares para el diagnóstico de infección por el virus de la influenza

En esta página

Antecedentes

Tests for influenza include molecular assays, rapid influenza diagnostic tests, immunofluorescence, viral culture or serology. Esta guía se centra en los ensayos moleculares para el diagnóstico de influenza ya que son cada vez más utilizados en centros clínicos (1). La reacción en cadena de la polimerasa-transcriptasa inversa (RT-PCR) y otros ensayos moleculares permiten identificar la presencia de ARN de influenza viral en muestras del sistema respiratorio. (Ver Tabla 1 below.) Some molecular assays are able to detect and discriminate between infections with influenza A and B viruses; other tests can identify specific seasonal influenza A virus subtypes [A(H1N1)pdm09, or A(H3N2)]. Estos ensayos pueden generar resultados en un lapso de 1 a 6 horas. Notablemente, la detección del ARN viral de la influenza por medio de estas pruebas no siempre indica la viabilidad del virus o la continua replicación viral de la influenza. Es importante señalar que no todos los ensayos han sido autorizados por la FDA para realizar diagnósticos. Los ensayos autorizados por la FDA se enumeran en Tabla 1.
1 En los Estados Unidos hay disponible un solo ensayo molecular de diagnóstico rápido aprobado por la FDA. Este ensayo tiene una alta sensibilidad y arroja resultados en 15 minutos.

Uso de pruebas en la toma de decisiones médicas

  • No es necesario hacer pruebas a todos los pacientes con signos y síntomas de influenza para tomar decisiones sobre tratamientos antivirales (ver Figura 1Figura 2). Una vez identificada la actividad de la influenza en la comunidad o en la zona geográfica, se puede realizar un diagnóstico clínico de la influenza para pacientes ambulatorios con signos y síntomas coherentes con sospechas de influenza, especialmente durante períodos de picos máximos de influenza en la comunidad. Rapid molecular assays (for example, the Alere i Influenza A&B that produces results in 15 minutes) or other  molecular assays that detect influenza viruses (such as the Cepheid or Biofire assays that produce results in one hour) are now becoming available in hospitals.
  • Si el tratamiento está indicado clínicamente, NO se debe impedir el tratamiento antiviral a los pacientes con diagnóstico presunto de influenza mientras se esperan los resultados de las pruebas durante los períodos de mayor actividad de la influenza en la comunidad cuando la probabilidad de influenza es alta. Encuentre más información acerca del tratamiento antiviral contra la influenza en Medicamentos antivirales, información para profesionales de los cuidados de salud.
    • Since results from molecular assays  may not always be available when initial therapy decisions must be made, antiviral treatment should be started as soon as possible because the greatest clinical benefit is when treatment is initiated as close to illness onset as possible, especially for patients at high risk of serious outcomes.
 Arriba

Pruebas de influenza en pacientes hospitalizados

  • Los pacientes hospitalizados con diagnóstico presunto de influenza y sin signos de enfermedad en las vías respiratorias inferiores deben someterse a la recolección de muestras de las vías respiratorias superiores para realizar pruebas de influenza. Encuentre más información acerca del tratamiento antiviral contra la influenza en Medicamentos antivirales, información para profesionales de los cuidados de salud.
  • Collection of lower respiratory tract specimens from hospitalized patients with suspected influenza and pneumonia can be considered for influenza testing by RT-PCR and other molecular assays if influenza testing of upper respiratory tract specimens is negative and if positive testing would result in a change in clinical management. En el caso de los pacientes hospitalizados con presunto diagnóstico de influenza o insuficiencia respiratoria en la asistencia respiratoria mecánica se debe recolectar una muestra mediante aspirado endotraqueal para detectar el virus de la influenza mediante RT-PCR si el diagnóstico de influenza no ha sido confirmado por un laboratorio. Los líquidos obtenidos mediante el lavado bronquioalveolar, recolectados para realizar otros diagnósticos, también pueden someterse a la prueba RT-PCR para detectar el virus de la influenza. Actualmente, el ensayo RT-PCR de los CDC está aprobado por la FDA para muestras del tracto respiratorio inferior; esta prueba está disponible únicamente en laboratorios de salud pública calificados (Ver Tabla 1, Ensayos RT-PCR y otros ensayos moleculares aprobados por la FDA para los virus de la influenza[305 KB, 6 páginas]). Los médicos pueden optar por solicitar otros ensayos aprobados por la FDA el uso fuera de etiquetas en la evaluación de muestras del tracto respiratorio inferior. La realización de estos ensayos para el análisis de dichas muestras no ha sido evaluada por la FDA; sin embargo, en algunas instituciones se puede acceder más fácilmente a estos ensayos.

Uso de muestras en la detección de brotes institucionales de influenza

  • Los ensayos moleculares como RT-PCR son particularmente útiles para identificar una infección por virus de la influenza como causa de brotes de problemas respiratorios en las instituciones (por ejemplo, asilos de ancianos, instalaciones de cuidados crónicos y hospitales).
  • Los resultados positivos de una o más personas enfermas con diagnóstico presunto de influenza pueden respaldar las decisiones de implementar de inmediato las medidas de prevención y control para brotes de influenza. Clinicians should be aware of requirements from their public health authorities regarding prompt notification of any suspected or confirmed institutional influenza outbreaks, and when respiratory specimens should be collected from ill persons and sent to a public health laboratory for laboratory confirmation of influenza.
 Arriba

Uso de muestras en la detección de casos de la nueva influenza A

  • Los ensayos moleculares, como la técnica RT-PCR, están diseñados para identificar con precisión el ARN viral de la influenza A y B utilizando genes conservados. Algunos ensayos detectarán los virus de la influenza A o B pero no determinarán el subtipo de virus de la influenza A, y por lo tanto, no podrán indicar si la infección se debe a un nuevo virus de la influenza tipo A. Novel influenza A viruses are antigenically and genetically distinct from currently circulating influenza A viruses among humans and usually represent zoonotic transmission from avian or swine species to humans.
  • Some FDA-cleared devices can not only detect influenza A or B viruses, but also can identify influenza A hemagglutinin genes, allowing for determination of some or all of the seasonal influenza A virus subtypes [i.e., A(H1N1)pdm09 or A(H3N2)]. These assays will not only identify the currently circulating influenza A virus strains, but also may identify viruses that are detected as influenza A for which no subtype could be identified. Estos virus "no clasificables" pueden representar infecciones por el virus de la nueva influenza A.
  • Clinicians and laboratorians using molecular assays that are capable of detecting all currently circulating seasonal influenza A virus subtypes [i.e., A(H1N1)pdm09 or A(H3N2)], and who identify an “unsubtypable” result (i.e., influenza A with no subtype detected), should contact their state or local public health laboratory immediately for additional testing to determine if the infection is due to a novel influenza A virus.
 Arriba

Factores que influyen en los resultados de los ensayos moleculares

Muchos factores pueden influir en los resultados de las pruebas de influenza. Influenza viral shedding in the upper respiratory tract generally declines substantially after 4 days in immunocompetent patients with uncomplicated influenza. Los pacientes con enfermedades de las vías respiratorias inferiores pueden pueden experimentar una replicación prolongada del virus de la influenza en las vías respiratorias inferiores. Immunosuppressed patients and persons receiving systemic corticosteroids can also have prolonged influenza viral replication in the lower respiratory tract. Molecular tests can detect influenza viral RNA (positive results) for a longer duration than other influenza testing (e.g., antigen testing - immunofluorescence or rapid influenza diagnostic tests). Although RT-PCR is the most sensitive influenza test and is highly specific, negative results can occur in persons with influenza for multiple reasons, so negative RT-PCR results may not always exclude a diagnosis of influenza. If clinical suspicion of influenza is high, antiviral treatment should continue in patients with severe illness or at high risk for complications while additional respiratory specimens are collected and influenza testing is performed.
Los factores que pueden influir en los resultados de las pruebas de influenza son:
  • Tiempo desde la aparición de la enfermedad hasta la recolección de muestras respiratorias para analizar
    • Respiratory specimens should ideally be collected as early as possible (ideally less than 4 days  after illness onset when influenza viral shedding is highest) in persons without lower respiratory tract disease and tested as soon as possible. Molecular assays may be able to detect influenza viral RNA in respiratory tract specimens longer than other influenza tests (e.g., after 72 hours from illness onset).
  • Fuente de las muestras de las vías respiratorias analizadas y manejo de muestras
  • Las mejores muestras de las vías respiratorias superiores para detectar el ARN viral de la influenza por RT-PCR y otros ensayos moleculares son los hisopados nasofaríngeos, lavados o aspirados; otras muestras aceptables son las que se obtienen mediante el hisopado nasal o faríngeo. No debe utilizarse un hisopo con mango de madera para recolectar muestras de las vías respiratorias debido a que pueden interferir con la RT-PCR y otras técnicas moleculares. Los médicos deben conocer las muestras clínicas aprobadas para el ensayo molecular utilizado y qué tipo de hisopados son los recomendados para usar con el ensayo tal como lo indican las instrucciones del fabricante incluidas en el ensayo.
  • Los pacientes hospitalizados con enfermedad de las vías respiratorias inferiores pueden tener una replicación prolongada del virus de la influenza en las vías respiratorias inferiores en comparación con las vías respiratorias superiores. En pacientes con enfermedad en las vías respiratorias inferiores, se deben recolectar y examinar muestras de las vías respiratorias inferiores si se sospecha influenza clínicamente y si el examen de las vías respiratorias superiores es negativo. Para los pacientes enfermos críticos con sospecha de influenza, incluso cuando las pruebas por RT-PCR u otros ensayos moleculares sean negativas, se deberá considerar la recolección de muestras respiratorias adicionales de varios sitios, en especial de las vías respiratorias inferiores (aspirado endotraqueal o lavado bronquioalveolar si se indica clínicamente para realizar otros diagnósticos) y se deberá examinar para encontrar virus de influenza por RT-PCR u otros ensayos molecuares. Debe seguirse con el tratamiento antiviral en dichos pacientes con pruebas adicionales de influenza pendientes.
  • Si la prueba se demora o se realiza en una instalación donde el paciente no está hospitalizado, las muestras deben colocarse en un medio de transporte estéril para virus, de acuerdo a las especificaciones de la prueba, y mantenerse refrigeradas hasta que se lleven al laboratorio lo antes posible. Se deben evitar o minimizar la congelación y descongelación para evitar el deterioro de los virus de la influenza si se realizará un cultivo viral.
  • Se deben seguir las instrucciones de fábrica, incluyendo muestras aceptables, manipulación y almacenamiento y procesamiento, para alcanzar un rendimiento óptimo de las pruebas. Las desviaciones de los procedimientos recomendados pueden ocasionar resultados negativos falsos.
 Arriba

Interpretación de los resultados de las pruebas

Las sensibilidades y las especificidades de RT-PCR y otros ensayos moleculares que han sido autorizadas por la FDA para uso diagnóstico son altas en comparación con otros ensayos autorizados por la FDA que utilizan métodos diferentes. Sin embargo, incluso con RT-PCR, puede haber resultados negativos falsos debido a recolecciones de muestras indebidas o poco cuidadosas o de una mala manipulación de la muestra luego de la recolección y antes de la prueba. También puede haber un resultado negativo en la prueba de una muestra recolectada cuando el paciente ya no tiene un virus detectable de la influenza. Puede haber resultados positivos falsos, aunque se dan rara vez (por ejemplo, debido a la contaminación del laboratorio u otros factores).
  • Resultado negativo
    • Un resultado negativo significa que no hay evidencia de ARN viral de la influenza en la muestra que se examinó. Para los pacientes hospitalizados, en especial para los pacientes con enfermedad en las vías respiratorias inferiores, si no se identifica ninguna otra etiología y todavía se sospecha clínicamente la presencia de influenza, se deben recolectar y examinar más muestras y se debe iniciar o continuar el tratamiento antiviral.
  • Resultado positivo
    • Un resultado positivo indica la detección de ARN viral de influenza, lo cual confirma la infección por virus de la influenza, pero no necesariamente significa la viabilidad del virus o que el paciente puede contagiar.
    • A positive result on testing an upper respiratory tract specimen in a person who recently received intranasal administration of live attenuated influenza virus vaccine (LAIV) may indicate detection of vaccine virus. LAIV contains influenza virus strains that undergo viral replication in respiratory tissues of lower temperature (e.g., nasal passages) than internal body temperature. Debido a que las fosas nasales se infectan con las cepas vivas del virus de la influenza de la vacuna durante la administración de LAIV, las muestras de las fosas nasales extraídas unos días después de la vacunación con LAIV pueden causar resultados positivos de influenza. Puede ser posible detectar cepas de la vacuna LAIV hasta 7 días después de la vacunación y, en casos menos frecuentes, por períodos mayores.
    • La interpretación de los ensayos moleculares de influenza dependerá de la prueba individual que se realice. Por ejemplo, un resultado negativo de un ensayo molecular de influenza que solo detecta el virus de la influenza A y el subtipo A(H1N1)pdm09 no descarta infección por el virus de la influenza B. Los médicos clínicos pueden consultar las descripciones detalladas de cada prueba autorizada por la FDA y qué puede o no puede significar el resultado.
 Arriba

Ventajas y desventajas de los ensayos moleculares

Ventajas:
  • Los ensayos moleculares son más sensibles y específicos para detectar los virus de la influenza que otras pruebas de influenza (por ejemplo, pruebas de diagnóstico rápido de la influenza, Inmunofluorescencia y cultivo viral).
  • Las probabilidades de un resultado positivo falso o negativo falso son bajas y, por consiguiente, la interpretación del resultado se ve menos afectada por el nivel de actividad de la influenza en la comunidad
  • Algunos ensayos moleculares, pero no todos, pueden distinguir entre subtipos específicos del virus de la influenza A
Desventajas:
  • Los resultados de RT-PCR y otros ensayos moleculares pueden no estar disponibles dentro de un tiempo clínicamente relevante para informar las decisiones de administración clínica.
  • RT-PCR and other molecular assays may not always  be available in all outpatient or emergency room settings. Para los pacientes hospitalizados, estos ensayos no siempre están disponibles en el lugar.
    • Es posible que las muestras respiratorias tengan que enviarse a un laboratorio estatal de salud pública o laboratorio comercial para RT-PCR. Por consiguiente, aunque la prueba puede arrojar resultados en 1-8 horas, el tiempo real para recibir los resultados puede ser mucho mayor.
  • La mayoría de los ensayos moleculares autorizados por la FDA no están aprobados para las muestras de las vías respiratorias inferiores
  • Por lo general, RT-PCR y otros ensayos moleculares son más costosos que otras pruebas de influenza
  • Algunos ensayos moleculares pueden no identificar de manera específica todos los subtipos de virus de influenza A que circulan actualmente. Según la prueba, un resultado negativo de un subtipo de virus de influenza A no descarta la infección con otro subtipo de virus de influenza A.
  • Algunos ensayos moleculares de influenza que se utilizan no están autorizados por la FDA y no se ha realizado una evaluación para conocer la precisión de todos los RT-PCR y ensayos moleculares disponibles. Se encuentra disponible una lista de todas las pruebas autorizadas por la FDA en laTabla 1, Ensayos RT-PCR y otros ensayos moleculares aprobados por la FDA para los virus de la influenza[305 KB, 6 páginas] .
 Arriba

Ensayos moleculares de detección rápida

Rapid molecular assays are a new type of molecular influenza diagnostic test for upper respiratory tract  specimens. These platforms use isothermal nucleic acid amplification and have high sensitivity and yield results in 15 minutes or less. Sensitivities of available rapid molecular assays range from 70-100%. Al igual que con otras pruebas moleculares de diagnóstico, si el tratamiento está indicado clínicamente, NO se debe impedir el tratamiento antiviral a los pacientes con diagnóstico presunto de influenza mientras se esperan los resultados de las pruebas durante los períodos de mayor actividad de la influenza en la comunidad cuando la probabilidad de influenza es alta. Encuentre más información acerca del tratamiento antiviral contra la influenza enMedicamentos antivirales, información para profesionales de los cuidados de salud.

Referencias

Ali T, Scott N, Kallas W, Halliwell ME, Savino C, Rosenberg E, Ferraro M, Hohmann E. Detection of influenza antigen with rapid antibody-based tests after intranasal influenza vaccination (FluMist). Clin Infect Dis. 1 de marzo de 2004 ;38(5):760-2.
Bell J, Bonner A, Cohen DM, Birkhahn R, Yogev R, Triner W, Cohen J, Palavecino E, Selva-rangan R. Multicenter clinical evaluation of the novel Alere™ i Influenza A&B isothermal nucleic acid amplification test. J Clin Virol. 2014 Sep;61(1):81-6.
Block SL, Yogev R, Hayden FG, Ambrose CS, Zeng W, Walker RE. Shedding and immunogenicity of live attenuated influenza vaccine virus in subjects 5-49 years of age. Vaccine. 8 de sept. de 2008 ;26(38):4940-6.
Ellis JSZambon MC. Diagnóstico molecular de la influenza. Rev Med Virol. Nov-Dic. de 2002; 12(6):375-89.
Hazelton B, Gray T, Ho J, Ratnamohan VM, Dwyer DE, Kok J. Detection of influenza A and B with the Alere i Influenza A & B: a novel isothermal nucleic acid amplification assay. Influenza and Other Respiratory Viruses 2015;9(3):151-4.
Mahony JB. Diagnóstico basado en la amplificación de ácido nucleico de las infecciones respiratorias por virus. Expert Rev Anti Infect Ther. Nov. de 2010; 8(11):1273-92.
Shu B, Wu KH, Emery S, Villanueva J, Johnson R, Guthrie E, Berman L, Warnes C, Barnes N, Klimov A, Lindstrom S. Design and performance of the CDC real-time reverse transcriptase PCR swine flu panel for detection of 2009 A (H1N1) pandemic influenza virus. J Clin Microbiol. Jul. de 2011 ;49(7):2614-9.
Talbot TR, Crocker DD, Peters J, Doersam JK, Ikizler MR, Sannella E, Wright PE, Edwards KM. Duration of virus shedding after trivalent intranasal live attenuated influenza vaccination in adults. Infect Control Hosp Epidemiol. Mayo de 2005 ;26(5):494-500.
Wang RTaubenberger JK. Methods for molecular surveillance of influenza. Expert Rev Anti Infect Ther. Mayo de 2010 ;8(5):517-27.

Información adicional

 Arriba
Cuadro 1. Ensayos RT-PCR y otros ensayos moleculares aprobados por la FDA para los virus de la influenza
ProductosFabricante(s)Tipo de virus de la influenza que detectaSubtipo(s) del virus de la influenza que diferenciaOtros virus respiratorios que identificaMuestras aceptables1Duración2/
complejidad3 de la prueba
Alere i NAT Flu A/B (CLIA Waived)AlereInfluenza A y BNingunoNingunoNasal swabs  (Direct)0.25h/
Certificado por la CLIA
Alere i NAT Flu A/B (Moderate)AlereInfluenza A y BNingunoNingunoNasal swabs (in VTM5)0.25 h/
moderada
 
Panel de Diagnóstico de influenza en humanos mediante RT-PCR en tiempo real de los CDC
(Influenza A/B Typing Kit4)
CDC, División de InfluenzaInfluenza A y BA/H1, A/H3, A/2009 H1, A/H5N1 (Asian LineageNingunoNasopharyngeal swabs, nasal swabs, throat swabs, nasal aspirates, nasal washes, dual nasopharyngeal/ throat swabs
broncheoalveolar lavages, bronchial washes, tracheal aspirates, sputum, lung tissue, and viral culture
~4 h/
High
CDC Human Influenza Virus Real-Time RT-PCR Detection and Characterization Panel
 
CDC, División de InfluenzaInfluenza AA/HI, A/H3,NingunoNasopharyngeal swabs, nasal swabs (in VTM5), or viral culture~4 h/
High
CDC Influenza A/H5 (Asian Lineage) Virus Real-Time RT-PCR  Primer and Probe SetCDC, División de InfluenzaInfluenza AA/H5N1 (linaje asiático)Ningunorespiratory specimens and viral culture~4 h/
High
CDC Influenza 2009 A(H1N1)pdm Real-Time RT-PCR PanelCDC, División de InfluenzaInfluenza A 2009 H1NingunoHisopados nasofaríngeos, hisopados nasales, aspirados nasales, lavados nasales, hisopados dobles nasofaríngeos/de garganta, lavados broncoalveolares, aspirados traqueales, lavados bronquiales y cultivos virales~4 h/
High
Ensayo para la influenza Cepheid XpertCepheidInfluenza A y BA/2009 H1NingunoNasopharyngeal swabs (in VTM5), nasal aspirates, and nasal washes,1.0 h/
moderada
Ensayo Cepheid Xpert Flu/RSV XCCepheidInfluenza A y BNingunoVirus respiratorio sincitialHisopados nasofaríngeos, lavados y aspirados nasales (en MTV)<1.0 h/
moderada
Panel de virus respiratorios (RVP) eSensor®GenMark Diagnostics, Inc.Influenza A y BA/HI, A/H3, A/2009 H1Virus sincitial respiratorio subtipo A, Virus sincitial respiratorio subtipo B, virus de parainfluenza 1, 2 y 3, metapneumovirus humano, especies B/E de adenovirus, especie C de adenovirus y rinovirus humanoNasopharyngeal swabs (in VTM5)~8 h/
High
Panel respiratorio FilmArrayBioFire Diagnostics, LLCInfluenza A y BA/HI, A/H3, A/2009 H1Virus sincitial respiratorio, virus de parainfluenza 1, 2, 3 y 4 metapneumovirus humano, rinovirus/enterovirus, adenovirus, coronavirus HKU1, coronavirus NL63Nasopharyngeal swabs (in VTM5)1.0 h/
moderada
Ibis PLEX-ID FluIbis/AbbottInfluenza A y BA/HI, A/H3, A/2009 H1NingunoNasopharyngeal swabs (in VTM5)~8 h/
High
IMDx Flu A/B y RSV para Abbottm2000IMDxInfluenza A y BA/HI, A/H3, A/2009 H1Virus respiratorio sincitialNasopharyngeal swabs (in VTM5)~4 h/
High
Ensayo IQuum Liat para influenza A/BIQuum/Roche Molecular DiagnosticsInfluenza A y BNingunoNingunoNasopharyngeal swabs (in VTM5)~0.5 h/
moderada
Prodesse PROFLU™+GenProbe/HologicInfluenza A y BNingunoVirus respiratorio sincitialNasopharyngeal swabs (in VTM5)<4h/
High
Prodesse ProFAST™+GenProbe/HologicInfluenza AA/HI, A/H3, A/2009 H1NingunoNasopharyngeal swabs (in VTM5)<4h/
High
Kit Qiagen Artus Influenza A/B Rotor-gene RT-PCRQiagenInfluenza A y BNingunoNingunoNasopharyngeal swabs (in VTM5)~4 h/
High
Ensayo Quidel Molecular Influenza A+BQuidelInfluenza A y BNingunoNingunoNasopharyngeal swabs and nasal swabs (in VTM5)~4 h/
High
Simplexa™ Flu A/B & RSVFocus Diagnostics, 3MInfluenza A y BNingunoRSVNasopharyngeal swabs (in VTM5)<4h/
High
Simplexa™ Flu A/B & RSV DirectFocus Diagnostics, 3MInfluenza A y BNingunoRSVNasopharyngeal swabs (in VTM5)<2h/
Moderada
Simplexa™ Influenza A H1N1 (2009)Focus Diagnostics,
3M
Influenza AA/2009 H1NingunoNasopharyngeal swabs, nasal swabs (in VTM5), and nasopharyngeal aspirates<4h/
High
U.S. Army JBAIDS Influenza A&B Detection Kit4Biofire DefenseInfluenza A y BNingunoNingunoNasopharyngeal swabs (in VTM5) and Nasopharyngeal washes~4 h/
High
U.S. Army JBAIDS Influenza A Subtyping Kit4Biofire DefenseInfluenza AA/HI, A/H3, A/2009 H1NingunoNasopharyngeal swabs (in VTM5) and Nasopharyngeal washes~4 h/
High
U.S. Army JBAIDS Influenza A/H5 Kit4Biofire DefenseInfluenza AA/H5N1 (linaje asiático)NingunoNasopharyngeal and throat swabs (in VTM5)~4 h/
High
Verigene® Respiratory Virus Nucleic Acid TestNanosphere, IncInfluenza A y BNingunoVirus sincitial respiratorio subtipo A, Virus sincitial respiratorio subtipo BNasopharyngeal swabs (in VTM5)3.5 h/
moderada
Verigene® Respiratory Virus Plus Nucleic Acid Test (RV+)Nanosphere, IncInfluenza A y BA/HI, A/H3, A/2009 H1Virus sincitial respiratorio subtipo A, Virus sincitial respiratorio subtipo BNasopharyngeal swabs (in VTM5)3.5 h/
moderada
Verigene® Respiratory Pathogen Nucleic Acid Test (RPFlex)Nanosphere, IncInfluenza A y BA/H1 (including H1 and 2009 H1), and A/H3Respiratory Syncytial Virus subtype A, Respiratory Syncytial Virus subtype B, Parainfluenza 1, 2 3, and 4 virus, Human Metapneumovirus, Adenovirus, and RhinovirusNasopharyngeal swabs (in VTM5)3.5 h/
moderada
Panel de virus respiratorios (RVP) x-TAG®Luminex Molecular Diagnostics Inc.Influenza A y BA/H1, A/H3Virus sincitial respiratorio subtipo A, Virus sincitial respiratorio subtipo B, virus de parainfluenza 1, 2 y 3, metapneumovirus humano, rinovirus y adenovirusNasopharyngeal swabs (in VTM5)~8 h/
High
x-TAG® Respiratory Viral Panel Fast (RVP FAST)Luminex Molecular Diagnostics Inc.Influenza A y BA/H1, A/H3Virus respiratorio sincitial, metapneumovirus humano, rinovirus y adenovirusNasopharyngeal swabs (in VTM5)~6 h/
High
  1. Estos tipos de muestras se especifican en los prospectos del productos habilitados por la Administración de Alimentos y Medicamentos de EE. UU. (FDA)
  2. La duración de la prueba incluye los tiempos reales de la prueba pero no los tiempos de traslado, manipulación, agenda de laboratorio ni generación de resultados. Los tiempos pueden variar según el proceso de extracción utilizado. Comuníquese con el laboratorio para ver los tiempos esperables para obtener los resultados.
  3. Las enmiendas de mejora de laboratorios clínicos exigen categorizar las pruebas por complejidad alta, moderada o certificada. Ref.: http://www.cms.gov/Regulations-and-Guidance/Legislation/CLIA/index.html
  4. Solo disponible para laboratorios DoD que califiquen, laboratorios de salud pública de los EE. UU. y laboratorios NREVSS que colaboren en la campaña.
  5. VTM = Viral transport media
Descargo de responsabilidad: Es posible que en este sitio encuentre algunos enlaces que le lleven a contenido disponible sólo en inglés. Además, el contenido que se ha traducido del inglés se actualiza a menudo, lo cual puede causar la aparición temporal de algunas partes en ese idioma hasta que se termine de traducir (generalmente en 24 horas). Llame al 1-800-CDC-INFO si tiene preguntas sobre la influenza estacional, cuyas respuestas no ha encontrado en este sitio. Agradecemos su paciencia






Guidance for Clinicians on the Use of RT-PCR and Other Molecular Assays for Diagnosis of Influenza Virus Infection | Health Professionals | Seasonal Influenza (Flu)



CDC. Centers for Disease Control and Prevention. CDC 24/7: Saving Lives. Protecting People.



Guidance for Clinicians on the Use of RT-PCR and Other Molecular Assays for Diagnosis of Influenza Virus Infection



On this Page

Background

Tests for influenza include molecular assays, rapid influenza diagnostic tests, immunofluorescence, viral culture or serology. This guidance focuses upon molecular assays for influenza as they are increasingly being used in clinical settings (1). Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA in respiratory specimens. (See Table 1below.) Some molecular assays are able to detect and discriminate between infections with influenza A and B viruses; other tests can identify specific seasonal influenza A virus subtypes [A(H1N1)pdm09, or A(H3N2)]. These assays can yield results in 1-6 hours. Notably, the detection of influenza viral RNA by these assays does not always indicate detection of viable virus or on-going influenza viral replication. It is important to note that not all assays have been cleared by the FDA for diagnostic use. FDA-cleared assays are listed in Table 1.
1 One FDA-cleared rapid molecular assay is available in the United States. This assay has high sensitivity and yields results in 15 minutes.

Use in Clinical Decision Making

  • Influenza testing is not needed for all patients with signs and symptoms of influenza to make antiviral treatment decisions (See Figure 1Figure 2). Once influenza activity has been identified in the community or geographic area, a clinical diagnosis of influenza can be made for outpatients with signs and symptoms consistent with suspected influenza, especially during periods of peak influenza activity in the community. Rapid molecular assays (for example, the Alere i Influenza A&B that produces results in 15 minutes) or other  molecular assays that detect influenza viruses (such as the Cepheid or Biofire assays that produce results in one hour) are now becoming available in hospitals.
  • If treatment is clinically indicated, antiviral treatment should NOT be withheld from patients with suspected influenza while awaiting testing results during periods of peak influenza activity in the community when the likelihood of influenza is high. More information about antiviral treatment of influenza is available at Antiviral Drugs, Information for Health Care Professionals.
    • Since results from molecular assays  may not always be available when initial therapy decisions must be made, antiviral treatment should be started as soon as possible because the greatest clinical benefit is when treatment is initiated as close to illness onset as possible, especially for patients at high risk of serious outcomes.
 Top of Page

Influenza Testing of Hospitalized Patients

  • Hospitalized patients with suspected influenza without lower respiratory tract disease should have upper respiratory tract specimens collected for influenza testing. More information about antiviral treatment of influenza is available at Antiviral Drugs, Information for Health Care Professionals.
  • Collection of lower respiratory tract specimens from hospitalized patients with suspected influenza and pneumonia can be considered for influenza testing by RT-PCR and other molecular assays if influenza testing of upper respiratory tract specimens is negative and if positive testing would result in a change in clinical management. Hospitalized patients with suspected influenza and respiratory failure on mechanical ventilation can have an endotracheal aspirate specimen collected for influenza testing by RT-PCR if a laboratory diagnosis of influenza has not been determined. Bronchoalveolar lavage fluid, if collected for other diagnostic purposes, can also be tested by RT-PCR for influenza viruses. Currently, only the CDC RT-PCR assay is FDA-cleared for lower respiratory tract specimens; this test is available only at qualified public health laboratories (see Table 1, FDA-cleared RT-PCR Assays and Other Molecular Assays for Influenza Viruses[305 KB, 6 pages] ). Clinicians may elect to order other FDA-cleared assays for off-label use in evaluating lower respiratory tract specimens. Performance of these assays for these specimens has not been evaluated by FDA; however, these assays may be more readily accessible at some institutions.

Use in Detecting Institutional Influenza Outbreaks

  • Molecular assays such as RT-PCR are particularly useful to identify influenza virus infection as a cause of respiratory outbreaks in institutions (e.g., nursing homes, chronic care facilities, and hospitals).
  • Positive results from one or more ill persons with suspected influenza can support decisions to promptly implement prevention and control measures for influenza outbreaks. Clinicians should be aware of requirements from their public health authorities regarding prompt notification of any suspected or confirmed institutional influenza outbreaks, and when respiratory specimens should be collected from ill persons and sent to a public health laboratory for laboratory confirmation of influenza.
 Top of Page

Use in Detecting Novel Influenza A Cases

  • Molecular assays, such as RT-PCR, are designed to accurately identify influenza A and B viral RNA by using conserved gene targets. Some assays will detect influenza A or B viruses but will not determine the influenza A virus subtype, and thus will not be able to indicate if the infection is due to a novel influenza A virus. Novel influenza A viruses are antigenically and genetically distinct from currently circulating influenza A viruses among humans and usually represent zoonotic transmission from avian or swine species to humans.
  • Some FDA-cleared devices can not only detect influenza A or B viruses, but also can identify influenza A hemagglutinin genes, allowing for determination of some or all of the seasonal influenza A virus subtypes [i.e., A(H1N1)pdm09 or A(H3N2)]. These assays will not only identify the currently circulating influenza A virus strains, but also may identify viruses that are detected as influenza A for which no subtype could be identified. These “unsubtypables” may represent novel influenza A virus infections.
  • Clinicians and laboratorians using molecular assays that are capable of detecting all currently circulating seasonal influenza A virus subtypes [i.e., A(H1N1)pdm09 or A(H3N2)], and who identify an “unsubtypable” result (i.e., influenza A with no subtype detected), should contact their state or local public health laboratory immediately for additional testing to determine if the infection is due to a novel influenza A virus.
 Top of Page

Factors Influencing Results of Molecular Assays

Many factors can influence influenza testing results. Influenza viral shedding in the upper respiratory tract generally declines substantially after 4 days in immunocompetent patients with uncomplicated influenza. Patients with lower respiratory tract disease may have prolonged influenza viral replication in the lower respiratory tract. Immunosuppressed patients and persons receiving systemic corticosteroids can also have prolonged influenza viral replication in the lower respiratory tract. Molecular tests can detect influenza viral RNA (positive results) for a longer duration than other influenza testing (e.g., antigen testing - immunofluorescence or rapid influenza diagnostic tests). Although RT-PCR is the most sensitive influenza test and is highly specific, negative results can occur in persons with influenza for multiple reasons, so negative RT-PCR results may not always exclude a diagnosis of influenza. If clinical suspicion of influenza is high, antiviral treatment should continue in patients with severe illness or at high risk for complications while additional respiratory specimens are collected and influenza testing is performed.
Factors that can influence influenza testing results are:
  • Time from illness onset to collection of respiratory specimens for testing
    • Respiratory specimens should ideally be collected as early as possible (ideally less than 4 days  after illness onset when influenza viral shedding is highest) in persons without lower respiratory tract disease and tested as soon as possible. Molecular assays may be able to detect influenza viral RNA in respiratory tract specimens longer than other influenza tests (e.g., after 72 hours from illness onset).
  • Source of respiratory specimens tested and specimen handling
  • The best upper respiratory tract specimens to detect influenza viral RNA by RT-PCR and other molecular assays are nasopharyngeal swabs, washes or aspirates; other acceptable specimens are a nasal and/or throat swab. A swab with a wood shaft should not be used for respiratory specimen collection because it may interfere with RT-PCR and other molecular assays. Clinicians should be aware of the approved clinical specimens for the molecular assay being used and what type of swabs are recommended for use with the assay as included in the manufacturer’s instructions included in the assay.
  • Hospitalized patients with lower respiratory tract disease may have prolonged lower respiratory tract influenza viral replication compared to the upper respiratory tract. In patients with lower respiratory tract disease, lower respiratory tract specimens should be collected and tested if influenza is clinically suspected and testing of upper respiratory tract specimens is negative. For critically ill patients with suspected influenza, even when testing by RT-PCR or other molecular assays is negative, consideration should be given to collecting additional respiratory specimens from multiple sites, especially lower respiratory tract (endotracheal aspirate, or bronchoalveolar lavage – if clinically indicated for other diagnostic purposes) and re-tested for influenza viruses by RT-PCR or other molecular assays. Antiviral treatment should be continued in such patients pending additional influenza testing.
  • If testing is delayed or is done at a facility other than where the patient is hospitalized, specimens should be placed in sterile viral transport media, consistent with test specifications, and refrigerated until transported to the laboratory for testing as soon as possible. Freezing and thawing should be avoided or minimized to avoid degradation of influenza viruses if viral culture will be performed.
  • Manufacturer's instructions, including acceptable specimens, handling, and storage and processing, should be followed to achieve optimum test performance. Deviations from recommended procedures may result in false negative results.
 Top of Page

Interpretation of Testing Results

Sensitivities and specificities of RT-PCR and other molecular assays that have been cleared by the FDA for diagnostic use are high compared to other FDA-cleared assays which use different methods. However, even with RT-PCR, false negative results can occur due to improper or poor clinical specimen collection or from poor handling of a specimen after collection and before testing. A negative result can also occur by testing a specimen that was collected when the patient is no longer shedding detectable influenza virus. False positive results, although rare, can occur (e.g., due to lab contamination or other factors).
  • Negative result
    • A negative result means that there is no evidence of influenza viral RNA in the specimen tested. For hospitalized patients, especially for patients with lower respiratory tract disease, if no other etiology is identified and influenza is still clinically suspected, additional specimens should be collected and tested, and antiviral treatment should be initiated or continued.
  • Positive result
    • A positive result indicates detection of influenza viral RNA, confirming influenza virus infection, but does not necessarily mean viable virus is present or that the patient is contagious.
    • A positive result on testing an upper respiratory tract specimen in a person who recently received intranasal administration of live attenuated influenza virus vaccine (LAIV) may indicate detection of vaccine virus. LAIV contains influenza virus strains that undergo viral replication in respiratory tissues of lower temperature (e.g., nasal passages) than internal body temperature. Since the nasal passages are infected with live influenza virus vaccine strains during LAIV administration, sampling the nasal passages within a few days after LAIV vaccination can yield positive influenza testing results. It may be possible to detect LAIV vaccine strains up to 7 days after vaccination, and in rare situations, for longer periods.
    • Influenza molecular assay interpretation will depend on the individual test that is performed. For example, a negative result from an influenza molecular assay that only detects influenza A virus and the A(H1N1)pdm09 subtype does not preclude infection with influenza B virus. Clinicians can consult for detailed descriptions of each FDA-cleared test and what the result may or may not signify.
 Top of Page

Advantages/Disadvantages of Molecular Assays

Advantages:
  • Molecular assays are more sensitive and specific for detecting influenza viruses than other influenza tests (e.g., rapid influenza diagnostic tests, immunofluorescence, and viral culture)
  • The likelihood of a false positive or false negative result is low and therefore, the interpretation of the result is less impacted by the level of influenza activity in the community
  • Some, but not all molecular assays can distinguish between specific influenza A virus subtypes
Disadvantages:
  • Results of RT-PCR and other molecular assays may not be available in a clinically relevant time frame to inform clinical management decisions.
  • RT-PCR and other molecular assays may not always  be available in all outpatient or emergency room settings. For hospitalized patients, these assays are not always available on-site.
    • Respiratory specimens may need to be sent to a state public health laboratory or commercial laboratory for RT-PCR. Therefore, although the test can yield results in 1-8 hours, the actual time to receive results may be substantially longer.
  • Most FDA-cleared molecular assays are not approved to test lower respiratory tract specimens
  • RT-PCR and other molecular assays are generally more expensive than other influenza tests
  • Some molecular assays may not specifically identify all currently circulating influenza A virus subtypes. Depending on the test, a negative result for one influenza A virus subtype may not preclude infection with another influenza A virus subtype.
  • Some influenza molecular assays being used are not FDA-cleared and an evaluation has not been performed to assess the accuracy of all available RT-PCR and molecular assays. A list of FDA-cleared tests is available in Table 1, FDA-cleared RT-PCR Assays and Other Molecular Assays for Influenza Viruses[305 KB, 6 pages] .
 Top of Page

Rapid Molecular Assays

Rapid molecular assays are a new type of molecular influenza diagnostic test for upper respiratory tract  specimens. These platforms use isothermal nucleic acid amplification and have high sensitivity and yield results in 15 minutes or less. Sensitivities of available rapid molecular assays range from 70-100%. As with other molecular diagnostic tests, if treatment is clinically indicated, antiviral treatment should NOT be withheld from patients with suspected influenza while awaiting testing results during periods of peak influenza activity in the community when the likelihood of influenza is high. More information about antiviral treatment of influenza is available at Antiviral Drugs, Information for Health Care Professionals.

References

Ali T, Scott N, Kallas W, Halliwell ME, Savino C, Rosenberg E, Ferraro M, Hohmann E. Detection of influenza antigen with rapid antibody-based tests after intranasal influenza vaccination (FluMist). Clin Infect Dis. 2004 Mar 1;38(5):760-2.
Bell J, Bonner A, Cohen DM, Birkhahn R, Yogev R, Triner W, Cohen J, Palavecino E, Selva-rangan R. Multicenter clinical evaluation of the novel Alere™ i Influenza A&amp;B isothermal nucleic acid amplification test. J Clin Virol. 2014 Sep;61(1):81-6.
Block SL, Yogev R, Hayden FG, Ambrose CS, Zeng W, Walker RE. Shedding and immunogenicity of live attenuated influenza vaccine virus in subjects 5-49 years of age. Vaccine. 2008 Sep 8;26(38):4940-6.
Ellis JSZambon MC. Molecular diagnosis of influenza. Rev Med Virol. 2002 Nov-Dec;12(6):375-89.
Hazelton B, Gray T, Ho J, Ratnamohan VM, Dwyer DE, Kok J. Detection of influenza A and B with the Alere i Influenza A & B: a novel isothermal nucleic acid amplification assay. Influenza and Other Respiratory Viruses 2015;9(3):151-4.
Mahony JB. Nucleic acid amplification-based diagnosis of respiratory virus infections. Expert Rev Anti Infect Ther. 2010 Nov;8(11):1273-92.
Shu B, Wu KH, Emery S, Villanueva J, Johnson R, Guthrie E, Berman L, Warnes C, Barnes N, Klimov A, Lindstrom S. Design and performance of the CDC real-time reverse transcriptase PCR swine flu panel for detection of 2009 A (H1N1) pandemic influenza virus. J Clin Microbiol. 2011 Jul;49(7):2614-9.
Talbot TR, Crocker DD, Peters J, Doersam JK, Ikizler MR, Sannella E, Wright PE, Edwards KM. Duration of virus shedding after trivalent intranasal live attenuated influenza vaccination in adults. Infect Control Hosp Epidemiol. 2005 May;26(5):494-500.
Wang RTaubenberger JK. Methods for molecular surveillance of influenza. Expert Rev Anti Infect Ther. 2010 May;8(5):517-27.

Additional Information

 Top of Page

Table 1. FDA-cleared RT-PCR Assays and Other Molecular Assays for Influenza Viruses
ProductsManufacturer(s)Influenza Virus Type DetectedInfluenza Virus Subtype(s) DifferentiatedOther Respiratory Viruses DifferentiatedAcceptable Specimens1Test Time2/
Complexity3
Alere i NAT Flu A/B (CLIA Waived)AlereInfluenza A and BNoneNoneNasal swabs  (Direct)0.25h/
CLIA Waived
Alere i NAT Flu A/B (Moderate)AlereInfluenza A and BNoneNoneNasal swabs (in VTM5)0.25 h/
Moderate
 
CDC Human Influenza Virus Real-Time RT-PCR Diagnostic Panel
(Influenza A/B Typing Kit4)
CDC Influenza DivisionInfluenza A and BA/H1, A/H3, A/2009 H1, A/H5N1 (Asian LineageNoneNasopharyngeal swabs, nasal swabs, throat swabs, nasal aspirates, nasal washes, dual nasopharyngeal/ throat swabs
broncheoalveolar lavages, bronchial washes, tracheal aspirates, sputum, lung tissue, and viral culture
~4 h/
High
CDC Human Influenza Virus Real-Time RT-PCR Detection and Characterization Panel
 
CDC Influenza DivisionInfluenza AA/HI, A/H3,NoneNasopharyngeal swabs, nasal swabs (in VTM5), or viral culture~4 h/
High
CDC Influenza A/H5 (Asian Lineage) Virus Real-Time RT-PCR  Primer and Probe SetCDC Influenza DivisionInfluenza AA/H5N1 (Asian lineage)Nonerespiratory specimens and viral culture~4 h/
High
CDC Influenza 2009 A(H1N1)pdm Real-Time RT-PCR PanelCDC Influenza DivisionInfluenza A 2009 H1NoneNasopharyngeal swabs, nasal swabs, nasal aspirates, nasal washes, dual nasopharyngeal/ throat swabs, broncheoalveolar lavages, tracheal aspirates, bronchial washes, and viral culture~4 h/
High
Cepheid Xpert Flu AssayCepheidInfluenza A and BA/2009 H1NoneNasopharyngeal swabs (in VTM5), nasal aspirates, and nasal washes,1.0 h/
Moderate
Cepheid Xpert Flu/RSV XC AssayCepheidInfluenza A and BNoneRespiratory Syncytial VirusNasopharyngeal swabs and nasal wash and nasal aspirate (in VTM)<1.0 h/
Moderate
eSensor® Respiratory Viral Panel (RVP)GenMark Diagnostics, Inc.Influenza A and BA/HI, A/H3, A/2009 H1Respiratory Syncytial Virus subtype A, Respiratory Syncytial Virus subtype B, Parainfluenza 1, 2, and 3 virus, Human Metapneumovirus, Adenovirus Species B/E, Adenovirus Species C, and Human RhinovirusNasopharyngeal swabs (in VTM5)~8 h/
High
FilmArray Respiratory PanelBioFire Diagnostics, LLCInfluenza A and BA/HI, A/H3, A/2009 H1Respiratory Syncytial Virus, Parainfluenza 1, 2, 3 and 4 virus, Human Metapneumovirus, Rhinovirus/Enterovirus, Adenovirus, Coronavirus HKU1, Coronavirus NL63Nasopharyngeal swabs (in VTM5)1.0 h/
Moderate
Ibis PLEX-ID FluIbis/AbbottInfluenza A and BA/HI, A/H3, A/2009 H1NoneNasopharyngeal swabs (in VTM5)~8 h/
High
IMDx Flu A/B and RSV for Abbottm2000IMDxInfluenza A and BA/HI, A/H3, A/2009 H1Respiratory Syncytial VirusNasopharyngeal swabs (in VTM5)~4 h/
High
IQuum Liat Influenza A/B AssayIQuum/Roche Molecular DiagnosticsInfluenza A and BNoneNoneNasopharyngeal swabs (in VTM5)~0.5 h/
Moderate
Prodesse PROFLU™+GenProbe/HologicInfluenza A and BNoneRespiratory Syncytial VirusNasopharyngeal swabs (in VTM5)<4h/
High
Prodesse ProFAST™+GenProbe/HologicInfluenza AA/HI, A/H3, A/2009 H1NoneNasopharyngeal swabs (in VTM5)<4h/
High
Qiagen Artus Influenza A/B Rotor-gene RT-PCR kitQiagenInfluenza A and BNoneNoneNasopharyngeal swabs (in VTM5)~4 h/
High
Quidel Molecular Influenza A+B AssayQuidelInfluenza A and BNoneNoneNasopharyngeal swabs and nasal swabs (in VTM5)~4 h/
High
Simplexa™ Flu A/B & RSVFocus Diagnostics, 3MInfluenza A and BNoneRSVNasopharyngeal swabs (in VTM5)<4h/
High
Simplexa™ Flu A/B & RSV DirectFocus Diagnostics, 3MInfluenza A and BNoneRSVNasopharyngeal swabs (in VTM5)<2h/
Moderate
Simplexa™ Influenza A H1N1 (2009)Focus Diagnostics,
3M
Influenza AA/2009 H1NoneNasopharyngeal swabs, nasal swabs (in VTM5), and nasopharyngeal aspirates<4h/
High
U.S. Army JBAIDS Influenza A&B Detection Kit4Biofire DefenseInfluenza A and BNoneNoneNasopharyngeal swabs (in VTM5) and Nasopharyngeal washes~4 h/
High
U.S. Army JBAIDS Influenza A Subtyping Kit4Biofire DefenseInfluenza AA/HI, A/H3, A/2009 H1NoneNasopharyngeal swabs (in VTM5) and Nasopharyngeal washes~4 h/
High
U.S. Army JBAIDS Influenza A/H5 Kit4Biofire DefenseInfluenza AA/H5N1 (Asian Lineage)NoneNasopharyngeal and throat swabs (in VTM5)~4 h/
High
Verigene® Respiratory Virus Nucleic Acid TestNanosphere, IncInfluenza A and BNoneRespiratory Syncytial Virus subtype A, Respiratory Syncytial Virus subtype BNasopharyngeal swabs (in VTM5)3.5 h/
Moderate
Verigene® Respiratory Virus Plus Nucleic Acid Test (RV+)Nanosphere, IncInfluenza A and BA/HI, A/H3, A/2009 H1Respiratory Syncytial Virus subtype A, Respiratory Syncytial Virus subtype BNasopharyngeal swabs (in VTM5)3.5 h/
Moderate
Verigene® Respiratory Pathogen Nucleic Acid Test (RP Flex)Nanosphere, IncInfluenza A and BA/H1 (including H1 and 2009 H1), and A/H3Respiratory Syncytial Virus subtype A, Respiratory Syncytial Virus subtype B, Parainfluenza 1, 2 3, and 4 virus, Human Metapneumovirus, Adenovirus, and RhinovirusNasopharyngeal swabs (in VTM5)3.5 h/
Moderate
x-TAG® Respiratory Viral Panel (RVP)Luminex Molecular Diagnostics Inc.Influenza A and BA/H1, A/H3Respiratory Syncytial Virus subtype A, Respiratory Syncytial Virus subtype B, Parainfluenza 1, 2, and 3 virus, Human Metapneumovirus, Rhinovirus, and AdenovirusNasopharyngeal swabs (in VTM5)~8 h/
High
x-TAG® Respiratory Viral Panel Fast (RVP FAST)Luminex Molecular Diagnostics Inc.Influenza A and BA/H1, A/H3Respiratory Syncytial Virus Human Metapneumovirus, Rhinovirus, and AdenovirusNasopharyngeal swabs (in VTM5)~6 h/
High
  1. These specimen types are specified in product package inserts cleared by the U.S. Food and Drug Administration (FDA)
  2. Test Time is inclusive of actual test time and is exclusive of transport, handling, laboratory run schedules, and generating results. Timing may vary depending on extraction process used. Contact laboratory for expected turn-around time.
  3. Clinical Laboratory Improvement Amendments require categorization of tests as waived, moderate or high complexity. Ref: http://www.cms.gov/Regulations-and-Guidance/Legislation/CLIA/index.html
  4. Available only to qualified DoD laboratories, U.S. public health laboratories, and NREVSS collaborating laboratories.
  5. VTM = Viral transport media

No hay comentarios:

Publicar un comentario