Skip to content

RPR Quantitative

Published: July 27, 2026Updated: August 25, 2026

The RPR (Rapid Plasma Reagin) Quantitative test measures the titer of antibodies produced in response to syphilis infection.

Quick summary

RPR Quantitative test measures antibody titers to diagnose syphilis.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
titer
Clinical utility
diagnostic
Result kind
semi_quantitative
FDA-cleared
Roche RPR Quant, Siemens RPR
interpretation: {"text":"A positive result indicates exposure to syphilis and requires further confirmation with a treponemal test.","label":"Positive"}; {"text":"A negative result suggests no current infection, but it may not rule out early-stage syphilis.","label":"Negative"}

The RPR Quantitative test is a blood test that detects the presence and quantity of antibodies, known as reagins, which are produced in response to syphilis infection. It is a non-treponemal test, meaning it does not directly detect the organism causing syphilis but rather the antibodies produced against it.

This test is often used as a screening tool due to its cost-effectiveness and ease of use. A positive RPR test is typically followed by a more specific treponemal test to confirm the diagnosis of syphilis.

The titer value, which is the measure of the dilution of the blood sample that still yields a positive result, helps in monitoring the progression of the disease and the effectiveness of treatment. A decreasing titer indicates successful treatment, while an increasing titer may suggest reinfection or treatment failure.

Frequently asked questions

How is the RPR Quantitative test performed?
The test is performed on a blood sample collected from a vein, usually in the arm.
What does a high titer mean?
A high titer indicates a higher concentration of antibodies, suggesting active or recent infection.
  1. 1
    CDC - Syphilis - STD InformationSource
  2. 2
    Mayo Clinic - Syphilis TestsSource

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 25, 2026. · Read our editorial policy