RSV testing is typically done using nasal swab samples and can involve a few different methods depending on the clinical situation. Here’s how testing is commonly performed and what to expect. What testing methods are used
- Rapid antigen (antigen) tests: Check nasal secretions for RSV proteins. These are fast, usually giving results within about 15 minutes to an hour, and are often used in clinics or urgent care settings. They’re quickest but can be less sensitive, especially in older children and adults. If the test is negative but suspicion remains high, a follow-up molecular test may be ordered.
- Molecular tests (NAATs, most commonly rRT-PCR): Detect RSV genetic material in a nasal or throat specimen. These tests are more sensitive and can detect lower levels of the virus, making them more reliable, especially in adults or later in the course of illness. Results may take a few hours to a day or more if sent to a central lab; some settings have rapid molecular testing that returns within a few hours.
- RSV antibody tests: Look for antibodies in the blood to see if someone has had RSV in the past or recently. They are not used to diagnose an active infection.
What sample collection involves
- Most RSV tests use a nose swab (nasopharyngeal or anterior nasal swab) to collect secretions. In some cases a throat swab may be used, or a combination of swabs. The procedure is fairly quick and may cause mild discomfort.
- Healthcare providers choose the sampling method based on the test type and the patient’s age and situation.
When testing is most useful
- In infants and young children, testing may help distinguish RSV from other respiratory viruses and guide management, especially if there are risk factors for severe disease.
- In older children and adults, testing is more likely to be considered if the result will influence care decisions, such as surveillance, isolation considerations, or antiviral use in specific settings.
- Testing is often interpreted alongside clinical assessment, time of year, severity of symptoms, and the presence of underlying conditions.
What the results mean
- Positive rapid antigen test: RSV infection confirmed; appropriate supportive care is typically recommended, with consideration of additional tests if necessary.
- Negative rapid antigen test but high clinical suspicion: A molecular test (PCR) may be performed to confirm, due to higher sensitivity.
- Positive molecular test (PCR): RSV infection confirmed; results can also be used for epidemiological tracking or co-testing for other respiratory pathogens if a panel was ordered.
- Antibody tests: Not used to diagnose current infection; indicate past exposure or immune response.
Key considerations
- Test choice may depend on age, symptoms, availability, and whether ruling out other infections is important.
- In some cases, healthcare providers may order a broader respiratory pathogen panel that tests for RSV plus other viruses (like flu and SARS-CoV-2) on the same sample.
- Timing matters: antigen tests are most accurate when viral load is high, typically early in the illness.
If you’d like, I can tailor this to a specific setting (clinic, urgent care, or home testing) or explain how testing decisions might differ for infants versus adults.
