The V.D.R.L. test. Significance of "rough" results.

During the past few decades many flocculation tests have been developed for use in the serological diagnosis of syphilis. Of these the one most widely used at the present time is the Venereal Disease Research Laboratory (VDRL) test, described by Harris, Rosenberg, and Riedel (1946) and Harris, Rosenberg, and Del Vecchio (1948) and named after the laboratory in which it was developed. The VDRL test can be performed either on a slide or in a tube, qualitatively or quantitatively. It can be carried out on serum or cerebrospinal fluid. It is undoubtedly the most useful screening test for syphilis available to-day; it is quick and easy to perform and requires a very small amount of serum or cerebrospinal fluid. In our laboratory the VDRL test does tend to be oversensitive, but as previously pointed out (Garner, 1966) this is no real drawback, especially when one test only is used to screen serum or cerebrospinal fluid and reference laboratory facilities are available for confirmation of results. In this study particular attention was paid to what are called "rough" reactions. These are tests in which the antigen particles are seen, at x 100 magnification, as single rods as well as a few irregular clumps of two or three rods in the one microscopic field. There is a distinct difference microscopically between "rough" clumps and the small even clumps which are reported as weakly reactive. It is normal to report tests showing this roughness as non-reactive.