c. Transport the specimen collected from the patient to the laboratory
immediately. Do NOT refrigerate the specimen.
2-14. TEST/PROCEDURES FOR SYPHILIS
a. Serologic Tests for Syphilis (STS). Over a dozen laboratory tests are
available to diagnose syphilis. Following is information about some of these tests.
(1) Venereal disease research laboratory (VDRL). This is the test which is
least expensive and most widely used. False positives, however, are common. Some
states use the VDRL test (or an equivalent blood test) as a screening test before
marriage. Additional conditions which indicate the need for a VDRL test include:
(a) Multiple sexual partners (a practice which increases the risk of
(b) An undiagnosed genital sore.
Another sexually transmitted disease.
(d) A history of contact with a partner who may have syphilis.
If the VDRL test is taken for any of the previous reasons, the test should be
repeated again in several weeks to be sure the individual tested did not have
an early syphilis infection which was missed.
(2) Rapid plasma region (RPR). Also inexpensive, this test is simple, rapid,
and a reliable substitute for the VDRL test.
Both the VDRL test and the RPR test are blood tests which can detect
antibody-like substances in the blood. Such substances form when a syphilis
infection is present. These two tests are inexpensive and easy to perform.
There is, however, a major disadvantage in these tests. The tests will NOT
detect syphilis in as many as 25 percent of the tested individuals who are in
the early stages of the disease. Additionally, many other conditions can
produce a false-positive test result. (False-positive means that the individual
has tested positive for syphilis but does not have syphilis.)
(3) Fluorescent treponemal antibody (FTA-ABS) test. This is the most
sensitive test, and false positives are uncommon. The FTA-ABS test, a more sensitive
and more specific blood test for detecting syphilis, is usually used to confirm the
presence of syphilis when either the VDRL or RPR result is positive. Even the FTA-
ABS test may not reveal a syphilis infection until three or more weeks after the disease