Evaluation of the Antigen-impregnated Discs For Patch Tests.

Antigen-impregnated discs (AlDs) have been developed to standardize the amount of antigen used for each patch test and also to make, the test far easier. in the first experiment, 800 patch tests were applied using, AlDs prepared for parthenium hysterophours, nitrofurazone, nickel sulphate, Potassium dichromate, Mercurochrome, acriflavine, garlic and onion, and the, results were compared with patch tests done with the corresponding standard antigens applied at the same, time in the same patients. In 780 instances, the results were similar with both Mvi of materials,- the:discrepancy being seen in only 20 cases. In a second experiment, AIDs prepared for nitrofurazone, garlic,, nickel sulphate, Calotropis procera, Mercurochrome and acriflavine were each divided into 3 s and stored at room 'soup temperature. 10 C and 420C respectively to study the I stability of AIDS under different climatic conditions. The results of patch tests with each of these'AIDS were compared with the standard antigens prepared at the same time and kept at IOOC. False negative patch tests were more frequent with the standard antigens indicating that AIDS are stable for at least I year at room temperature even when the environmental temperature is as high as 429C.