Inter-laboratory evaluation of serological tests for syphilis in India: Final report on 1953-55 inquiry

The author describes an investigation, carried out in 1953-55 under the sponsorship of the Indian Council of Medical Research, to determine the relative merits of the serological tests for syphilis in current use in the major laboratories in India. Eight laboratories were included in the survey and in each the same three tests-the Wassermann test, the Kahn standard test, and the VDRL slide precipitation test-were evaluated as to specificity, sensitivity and reproducibility. In all, 921 serum samples were examined: 376 from syphilitics, 86 from patients with non-syphilitic venereal disease, 265 from patients with non-venereal diseases, and 194 from apparently normal donors.The VDRL test proved to be the most satisfactory on the average (specificity, 97.6%; sensitivity, 95.2%; reproducibility, 87.2%) and it is therefore recommended that this test be adopted as the only routine serological test in all laboratories. From the considerable inter-laboratory variations observed in the results, it is obvious that there is room for improvement in the standard of technical performance in most of the laboratories. The author suggests that by reducing the number of different tests used to a minimum, improvement and standardization of techniques would be facilitated.