Parainfluenza Tests Test

Parainfluenza tests check if a parainfluenza virus is causing your respiratory illness. These viruses are a common cause of cold-like symptoms, especially in children, but can cause serious illness in older adults or people with weakened immune systems.

What this test measures

Parainfluenza tests measure the presence of parainfluenza viruses (HPIVs) in a sample of fluid from your nose or mucus from your lungs. They help determine if a parainfluenza virus is causing your respiratory symptoms.

What your results mean

Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.

Higher-than-normal results

A positive result means you likely have a parainfluenza infection. However, a PCR test can sometimes show signs of the virus even if you don't have enough virus to make you sick.

Lower-than-normal results

A negative result means no signs of parainfluenza viruses were found, but it does not rule out an infection because there may have been too little virus in the sample.

Frequently asked questions

What are parainfluenza viruses?

Parainfluenza viruses are a group of four types of viruses that commonly cause respiratory illnesses, especially in babies and young children.

How is the test done?

The test usually uses a sample of fluid from your nose or mucus from your lungs.

Who should get tested?

People at high risk for serious illness, such as those with weakened immune systems, heart or lung disorders, or older adults, may need testing.

What does a positive result mean?

A positive result means you likely have a parainfluenza infection, but it's possible to have a positive test without being sick.

Can a negative result be wrong?

Yes, a negative result does not rule out a parainfluenza illness because there may be too little virus in the sample to detect.

Sources

MedlinePlus: Parainfluenza Tests — NIH MedlinePlus

Last updated July 7, 2026. Information is aggregated from official public sources and is not a substitute for professional medical care.