Normal Values:

A negative test result is considered normal. However, the body does not always produce antibodies specifically in response to the syphilis bacteria, so the test is not always accurate. False-negatives may occur in persons with early- and late-stage syphilis. More testing may be needed before ruling out syphilis.

What abnormal results mean:

A positive test result may mean that you have syphilis. If the screening test is positive, the next step is to confirm the diagnosis with a more specific test for syphilis, such as FTA-ABS. The FTA-ABS test will help distinguish between syphilis and other infections.

How well the RPR test can detect syphilis depends on the stage of the disease. The test is most sensitive -- almost 100% -- during the middle stages of syphilis. It is less sensitive during the earlier and later stages of the disease.

Some conditions may cause a false positive test, including:

• HIV
• Lyme disease
• Certain types of pneumonia
• Malaria
• Systemic lupus erythematosus