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W H:EN quantitative serologic tests for syphilis caine into general use in the early 1940's, clinicians were immediately confronted with the problem of interpreting serologic reports which indicated low titer results. Some physicians are prone to consider the low titer results of Venereal Disease Research Laboratory (VDRL) quantitative tests as biologic false positive reactions when the patient has no clinical or historical evidence of syphilis infection. Because it has been our impression that manly of the so-called false positive reactions are in fact evidence of infection, we decided to interpret, by reference tests, a series of specimens which yielded low titer results. Kolmer Reiter protein (KRP) and fluorescent treponemal antibody (FTA) tests were performed on 1,000 c.onsecutive blood specimens wlhich gave reactions in the range of 1 to 4 dilutions with the VDRL tube test. The physicians and clinicians who had submitted the specimens were asked to complete a form including information as to previous history of disease and treatment, present evidence of syphilis, spinal fluid findings, if performed, and their diagnosis of the case. They were not informed of the results of the KRP and PTA tests, and the information they submitted was not given to the laboratory personnel. Because it was not possible to obtain clinical information for some of the persons whose blood specimens were submitted and because of duplicate specimens from a few persons in the original 1,000, the final study group consisted of 842 persons. Besides the KRP and FTA tests, Treponema pallidwm immobilization (TPI) tests were performed on second blood specimens from 96 selected persons. Also, as a control, KRP and FTA tests were conducted oni 100 consecutive blood specimens which had previously shown nonreactive results with the VDRL test. In April 1951 the division of laboratories of the Tennessee Departmelnt of Public Health replaced the Kahn standard quantitative test for routine diagnosis with the VDRL tube quantitative test, which is performed according to the recommended technique (1). We have found that the VDRL test has consistently shown good reproducibility, and it has agreed well with control performance on individual serums, as demonstrated in the annual Public Health Service standard serologic evaluation study. The VDRL tube test is used rather thani the VTDRL slide test because it has better reproducibility. This usage is particularly true The authors are on the staff of the Tennessee Department of Public Health, Nashville. Dr. Tucker is deputy commissioner and director, division of preventable diseases. Dr. Cameron is director, Mr. Buchanan is associate director, and Mr. Grayson is a microbiologist, division of laboratories. Miss Dillon is director of statistical service. The study was made possible through the cooperation and technical assistance of the Venereal Disease Research Laboratory, Public Health Service, Chamblee, Ga. |
