Delayed hypersensitivity skin testing: response rates in a surgical population.

The results of this study indicate that skin test responses should be measured at both 24 and 48 hours post-injection and considered reactive or positive if induration of greater than or equal to 5 mm. is noted at either time. The practice of measuring responses at 48 hours only is neither appropriate nor recommended as it may produce a large percentage of false negative results. Erythema without induration was noted in a small percentage of patients. Future studies should evaluate the efficacy of erythema greater than or equal to 15 mm. in the absence of induration as a reactive response to mumps antigen. The validity of data interpretation must ultimately be based on correlations with morbidity and mortality. Streptokinase-streptodornase, mumps, and trichophyton were the three antigens with highest response rates, and this battery detected 94% of the reactive or positive responses to the five-antigen battery.