Syphilis Tests

Microhemagglutination assay (MHA-TP), (Syphilis Test), Rapid Plasma Reagin (RPR) Test, (Syphilis Test), Venereal Disease Research Laboratory (VDRL) Test, (Syphilis Test)

What To Think About

• An untreated syphilis infection during pregnancy can infect the baby.
  • The risk of infection is greatest when the mother has an early stage of syphilis.
  • If a pregnant woman receives treatment before the 16th week of pregnancy, the baby usually will not have syphilis.
  • Untreated infection during pregnancy can cause miscarriage, premature birth, stillbirth, or birth defects.
• If a screening test is positive (reactive), the strength of the result may be determined by measuring the amount of reagin. The results are then given in titers. A titer is a measure of how much the blood or spinal fluid sample can be diluted before the reagin can no longer be detected.
  • A titer of 1 to 16 (1:16) means that reagin can be detected when 1 part of the blood or spinal fluid sample is diluted by up to 16 parts of a salt solution (saline).
  • A larger second number means there is more reagin in the sample and generally indicates a higher level of infection. Therefore, a titer of 1 to 64 indicates more reagin, and a more intense infection, than a titer of 1 to 16.
• A reactive or positive test result does not always mean that you have syphilis. Other conditions can cause positive screening test results, including injecting illegal drugs, recent vaccinations, pregnancy, endocarditis, autoimmune diseases (such as systemic lupus erythematosus), tuberculosis, mononucleosis, leprosy, malaria, hepatitis, Lyme disease, and rheumatoid arthritis.
• Fluid from a sore that may be caused by syphilis sometimes is collected and examined with a special type of microscope (darkfield microscope).
• Screening for syphilis and other sexually transmitted diseases (STDs) often is done for people who engage in high-risk sexual behaviour. If you have syphilis, your sex partner or partners should be notified, tested, and treated to prevent serious complications and to stop the spread of the disease.
• With treatment, a positive reagin (VDRL and RPR) syphilis test result usually becomes negative. Positive treponemal (FTA-ABS, MHA-TP, TPPA) tests stay positive for a lifetime.
• Sores caused by syphilis (chancres) make it easier to get and transmit an HIV infection.
• People with HIV infection who have a negative VDRL test should have a second test for syphilis if the infection is suspected.
• All provinces require health professionals to report all cases of syphilis to the local health unit. In some provinces, health professionals are also required to ask for the names and addresses of your recent sex partners. If you have syphilis, the health unit may contact you to ensure that you undergo treatment. If you give the names of your sex partners to your doctor or the health unit, they will be contacted in confidence by the health unit and advised to have a test for syphilis.

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Author:	Kathe Gallagher, MSW Maureen Shea	Last Updated: November 27, 2007
Medical Review:	Kathleen Romito, MD - Family Medicine Jeanne Marrazzo, MD, MPH - Infectious Disease Andrew Swan, MD, CCFP, FCFP - Family Medicine
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