THE INCIDENCE AND ETIOLOGIC BACKGROUND OF CHRONIC BIOLOGIC FALSE-POSITIVE REACTIONS IN SEROLOGIC TESTS FOR SYPHILIS: PRELIMINARY REPORT*

PRESENT standard serologic tests for syphilis (hereafter abbreviated STS), routinely discovered in patients who have no history or physical evi-dence of that infection, may represent either latent syphilis, acquired or con-genital, or biologic false-positive reactions (hereafter abbreviated BFP). BFP reactors may be divided into two categories, acute and chronic.1 The acute reactions are due to a large number of infections, bacterial, viral, plasmodial, rickettsial or protozoal. They appear during or immediately after such a precipitating infectious cause, and regress spontaneously to nor-mality within a brief period, not exceeding six months. Chronic BFP reactors, on the other hand, are characterized by the usual absence of any of the commonly known precipitating causes of acute BFP reactions, and by the fact that the false-positive STS, instead of disappearing spontaneously, persists over a period of years, perhaps for a lifetime. This paper is concerned in preliminary fashion with the identification of the chronic BFP reactor by the use of the treponemal immobilization test