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Serum Reagin Antibody Titration (for Syphilis Screening)

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

This test measures the presence and level of reagin antibodies in your blood, which may indicate exposure to *Treponema pallidum*—the bacteria responsible for syphilis. It’s often used as a screening tool to check for early infection.

Quick summary

["A simple blood test to detect early syphilis infection by checking for specific antibodies."]

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

Key facts at a glance

LOINC
47476-7
Short code
Reagin Ab Titr Spec
Synonyms
Reagin Ab Titr Spec
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

What This Test Measures

Reagin antibodies are non-specific markers produced by the immune system in response to syphilis infection. This test quantifies their concentration in your serum, helping identify whether you may have been exposed to the bacteria causing syphilis. Unlike specific treponemal tests, reagin tests are less precise but useful for initial screening due to their sensitivity in early stages.

How the Test Works

Your blood sample is analyzed using a qualitative or semi-quantitative method (often a fluorescent treponemal antibody absorption, FTA-ABS-like approach) to detect reagin antibodies. The result is reported as a positive, negative, or borderline, which helps guide further testing if needed.

When You Might Need This Test

Your healthcare provider may recommend 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’s also used during pregnancy to screen for syphilis in expectant mothers.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted to draw blood from a vein in your arm. The process takes about 5 minutes, and you may feel a brief pinch. If you’re pregnant, let your provider know before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Syphilis Antibody Test (Reagin Titration)

Frequently asked questions

Why might my doctor order this test?
Your doctor may order this test to screen for syphilis, especially if you have symptoms, risk factors, or are part of a group at higher risk. While reagin tests are less specific than other syphilis tests, they can help identify early infection when other tests may not yet show results. If positive, further testing (like a specific treponemal antibody test) will be needed to confirm diagnosis.
What does a positive result mean?
A positive reagin test suggests possible syphilis infection, but it doesn’t confirm the diagnosis alone. You’ll likely need additional tests to determine if you have active syphilis or past exposure. Treatment options depend on the stage of infection and may include antibiotics.
Can I get syphilis from a positive reagin test?
No, a positive reagin test does not mean you currently have syphilis. It only indicates that your immune system may have detected past or early exposure to the bacteria. Always follow up with your healthcare provider for proper evaluation and treatment if needed.
  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