Influenza other diagnostic studies

Influenza Microchapters
Home
Patient Information
Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating Influenza from other Diseases
Epidemiology and Demographics
Risk Factors
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Chest X Ray
Other Diagnostic Studies
Treatment
Medical Therapy
Primary Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Case Studies
Case #1
Influenza other diagnostic studies On the Web
Most recent articles
Most cited articles
Review articles
CME Programs
Powerpoint slides
Images
American Roentgen Ray Society Images of Influenza other diagnostic studies All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
US National Guidelines Clearinghouse
NICE Guidance
FDA on Influenza other diagnostic studies
CDC on Influenza other diagnostic studies
Influenza other diagnostic studies in the news
Blogs on Influenza other diagnostic studies
Directions to Hospitals Treating Influenza
Risk calculators and risk factors for Influenza other diagnostic studies

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Alejandro Lemor, M.D. [2]

Other Diagnostic Studies

Molecular Assays Adapted from CDC

• Tests for influenza include molecular assays, rapid influenza diagnostic tests, viral culture or serology.
• Molecular assays for influenza are increasingly being used in clinical settings.
• Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and other molecular assays can identify the presence of influenza viral RNA in respiratory specimens.
• RT-PCR is particularly useful to identify influenza virus infection as a cause of respiratory outbreaks in institutions, such as nursing homes, chronic care facilities, and hospitals.
• Some molecular assays are able to detect and discriminate between infections with influenza A and B viruses; other tests can identify specific influenza A virus subtypes [A(H1N1)pdm09, seasonal A (H1N1), or seasonal A (H3N2)].
• These assays can yield results in 3-8 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.

Advantages	Disadvantages
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	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 are generally not available for 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 3-8 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.