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INTRODUCTION
This article is intended to provide a basic understanding of two of the most common serologie tests for syphilis (STS) and guidelines for their interpretation. The report of a positive syphilis test has implications and repercussions beyond strict medical considerations. How employées are informed and what they are told about the significance of the test results will determine the amount of distress to both themselves and their partners. Undue anxiety may be averted by the nurse who is aware that a positive test may not indicate luetic infection.
TYPES OF SEROLOGIC TESTS
When invaded by the syphilitic organism Treponema pallidum, the human host responds with production of multiple antibodies, some of which are specific to treppnemal infections and others which may be found in a variety of other conditions. Generally, serologìe tests for syphilis are divided into two categories, nontreponemal and treponema! tests, depending upon the type of antibody they detect.1 The nonireponema) tests are usually performed initially and positive results are confirmed by treponema! tests.
The nontreponemal tests detect a substance called reagin which is a nonspecific immunoglobulin of the IgG/IgM class.2 Of this type of test, the Wasserman reaction was the first, introduced in 1906. The most widely used nontreponema] test currently is the VDRL (Venereal Disease Research Laboratory) slide test. Results are reported qualitatively For screening and quantitatively for diagnostic purposes or for following response to treatment. The qualitative reports are stated nonreactive (NR), weakly reactive (WR) or reactive (R). Some laboratories automatically perform quantitative measurements if any reactivity is seen. The quantitative measurements are reported as titres representing the highest dilution at which the test is fully reactive. Thus a titre of 1:16 means that the serum was reactive at a dilution of 1:16, but not at a dilution of 1:32.
Of the treponemal tests, the FTA-ABS Fluorescent Treponemal Antibody Absorption) test is the standard. The FTA-ABS establishes the presence of specific antitreponemal antibodies in the serum. Because of its...