Skip to content

Antibody Titration to Serological Antigen (e.g., *Rheumatoid Factor* or *Antistreptolysin O*)

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

This test measures the strength of your immune system’s response to certain proteins or bacteria, often used to diagnose or monitor conditions like autoimmune diseases or infections.

Quick summary

Helps detect immune system activity linked to infections or autoimmune conditions.

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

Key facts at a glance

LOINC
5371-0
Short code
ASO Ab Titr Ser LA
Synonyms
ASO Ab Titr Ser LA
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
la
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

What This Test Measures

Your blood sample is tested for the presence of antibodies that target specific antigens (proteins). The result indicates how strongly your immune system is reacting, often expressed as a dilution factor (e.g., 1:160, 1:800).

How the Test Works

The test uses an immunoassay method to detect and quantify antibodies in your serum. A positive result suggests an active immune response, while a negative result indicates no detectable antibodies.

Common Uses

This test is commonly used to diagnose or monitor conditions like rheumatoid arthritis, lupus, or past infections (e.g., strep throat). It may also help assess immune responses to vaccines or chronic illnesses.

When You Might Need This Test

Your doctor may order this test if you have symptoms of autoimmune diseases, recurrent infections, or if you’re being evaluated for conditions like rheumatoid arthritis, lupus, or past bacterial infections.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Rheumatoid Factor or ASO Titration

Frequently asked questions

Why might my test results be important?
High antibody levels can signal an ongoing immune response, which may require further evaluation for conditions like autoimmune diseases or chronic infections. Low or absent levels may indicate no active immune reaction to the tested antigen.
What do my results mean?
Results are typically reported as a dilution factor (e.g., 1:100, 1:10,000). A higher dilution means stronger antibody presence. Your doctor will interpret results in the context of your symptoms and medical history.
How often do I need this test?
The frequency depends on your condition. Some patients need this test yearly, while others may require it more often if their condition is unstable or worsening.
  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