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Antibody Screening for Syphilis (Qualitative)

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

This test detects antibodies in your blood that may indicate past or current syphilis infection. It helps healthcare providers assess exposure or infection risk.

Quick summary

["A simple blood test to check for syphilis-related antibodies."]

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

Key facts at a glance

LOINC
9788-1
Short code
ASO Ab Ser Ql
Synonyms
ASO Ab Ser Ql
Category
coagulation
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

What This Test Measures

The test looks for specific antibodies (called antistreptolysin O, or ASO) produced by your immune system in response to certain bacteria. These antibodies can appear after infection with *Treponema pallidum*, the bacterium that causes syphilis.

How the Test Works

This is a qualitative test, meaning it provides a yes/no result rather than a measured value. If antibodies are present, the test may indicate exposure to syphilis bacteria.

Why It’s Done

Healthcare providers may order this test if you have symptoms of syphilis (e.g., sores, rashes, or flu-like illness), a history of sexually transmitted infections (STIs), or if you’re at higher risk (e.g., unprotected sex, multiple partners). It can also be part of routine screening in certain settings.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm, and a blood sample will be drawn. The process takes a few minutes, and you may feel slight discomfort.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

ASO Screen (Qualitative)

Frequently asked questions

This test helps diagnose syphilis by identifying antibodies that your body produces after infection. While it can indicate past exposure, it may not always show current infection. Results should be interpreted by a healthcare provider alongside clinical symptoms and other tests.
This test is qualitative, meaning it only tells you if antibodies are present (positive) or not (negative). It does not provide a quantitative measure of antibody levels.
A positive result suggests possible past or current syphilis infection. Follow-up testing (like a confirmatory Treponema pallidum antibody test) may be needed to confirm diagnosis.
A negative result means no detectable antibodies were found in this test, but syphilis could still be present in early stages or without antibody production. Your provider may recommend retesting or additional tests.
How long will I need to wait for results?
Results are typically available within 24 to 48 hours, but timing may vary by lab. Your healthcare provider will discuss the results with you.
  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