title: Stability of mammalian tuberculin PPD.
abstract: Six lots of PPD prepared in 1937 met the requirements when tested in guinea pig potency assay in 1974. Reading of the skin reactions at 48 hr gave more consistent results than the 24 hr reading. Data were evaluated by analysis of variance and by a quick method developed for the estimation of identity of the standard and the test preparation. Although less sensitive than the analysis of variance, the quick method has been found suitable for estimation of the potency of tuberculin preparations.
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004355:Drug Stability; D005260:Female; D006168:Guinea Pigs; D008297:Male; D013223:Statistics as Topic; D014373:Tuberculin; D014374:Tuberculin Test
chemical_list: D014373:Tuberculin