Coccidioidin retest reaction. Observations of tests on a coccidioidin-sensitive person.

The retest coccidioidin reaction in an apparently healthy person known to be coccidioidin-positive developed more quickly and was of a greater magnitude than that of an equivalent test in a virginal site in the same person. In both reactions, erythema, induration and/or edema were evident. Although the peak of the retest reaction was at 12 hours, readings made at 24 and 48 hours were in a definitively positive category.