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Respiratory Syncytial Virus Antibody, Serum or Plasma (Quantitative Titration)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of antibodies your body produces in response to the respiratory syncytial virus (RSV), a common virus that can cause respiratory infections.

Quick summary

["Antibodies help your immune system recognize and fight RSV if you come into contact with it again."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
24299-0
Short code
RSV Ab sp2 Titr Ser
Synonyms
RSV Ab sp2 Titr Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of RSV infection, such as a runny nose, cough, or difficulty breathing, especially if you’re at higher risk for severe illness. It can also be used to assess immunity in certain groups, like infants, elderly adults, or those with weakened immune systems.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. The sample is taken from either your serum (liquid part of blood after clotting) or plasma (liquid part after blood is centrifuged).

How the Test Works

The test uses a method called titration to measure the exact concentration of RSV antibodies in your blood. This helps determine how strongly your immune system has responded to the virus.

What the Results Mean

Results are reported as a quantitative value indicating the antibody level. Higher values suggest a stronger immune response, while lower values may indicate no prior exposure or a weaker response.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

RSV Antibody Level (Serum/Plasma)

Frequently asked questions

What does a positive result mean?
A positive result means your body has produced antibodies against RSV, indicating you’ve either had the virus before or received immunity through vaccination. This doesn’t necessarily mean you’re currently infected but shows your immune system has recognized the virus.
How long do RSV antibodies last?
RSV antibodies typically decline over time after infection or vaccination. Their persistence depends on factors like immune health and exposure history. Some people may have detectable levels for months or years, while others may lose them faster.
Can this test be used to diagnose an active RSV infection?
While this test measures antibodies, it’s not typically used to diagnose an active RSV infection. For active infection, other tests like viral testing (e.g., PCR) are usually preferred, as they detect the virus itself rather than your immune response.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy