Monotest Compared to Standard PPD, 5TU, Mantoux Test

ABSTRACT

The Monotest was compared with the Mantoux test. A total of 404 primary school children were subjected to test. Each child was innoculated simultaneously to one side arm with purified protein derivative (PPD, 5TU) and to the another side arm with Monovacc(Institut Merieux). Results from each test were read seperately 72 hours after administration. When induration of 2mm or greater was considered a positive Monotest reaction and compared to a positive Mantoux reaction of 10mm or greater, the sensitivity of Monotest to Mantoux test was 91.56% and the specificity was 71.85%. When induration of 5mm or greater was considered a positive Monotest reaction and compared to a positive Mantoux reaction of 10mm or greater, the sensitivity of Monotest to Mantoux test was 42.77% and the specificity was 94.53%. From these results I would assume that the Monotest can be substituted for Mantoux test (PPD, 5TU) as screening test, preferably 2mm or greater induration of Monotest is considered as a positive result. All children with doubtful or positive reactions to a Monotest should be retested using the Mantoux technique because of relative high false positive rate.