Parainfluenza Tests
Reviewed
Parainfluenza tests check whether a parainfluenza virus is causing a respiratory illness. These viruses are common in spring, summer, and fall and can cause cold-like symptoms, croup, bronchitis, or pneumonia, especially in people with weakened immune systems or certain medical conditions. The most common test is a molecular (PCR) test that detects genetic material of the virus.
Preparation and collection
No special preparation is needed for most parainfluenza tests. If you are having a bronchoalveolar lavage (BAL), you may need to fast for several hours before the test and arrange for someone to drive you home because you may receive medicine to help you relax.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- Rapid antigen tests are less accurate and must be done within a week after symptoms begin.
- Viral culture tests take much longer than other tests.
- Blood tests are mainly used for research.
- A negative result does not rule out infection; a positive result may not always indicate active illness.
What to do next
Talk with your healthcare provider about what your test results mean and any follow-up care you may need.