Reactivity of Dade rapid plasma reagin card test with low-titer sera.

Of 105 sera having reagin titers of 1 dilution as determined by the rapid plasma reagin 18-mm circle card test (Hynson, Westcott and Dunning, Baltimore, Md.), 103 (98.1%) were reactive with the Dade rapid plasma reagin card test (Biokit Laboratories, Barcelona, Spain), indicating that the two procedures are comparable in their ability to detect low levels of nontreponemal syphilitic antibody, or reagin.