Comparison between serum and urinary sulphadimidine acetylation as predictors of isoniazid acetylator status in patients with pulmonary tuberculosis.

ABSTRACT

The acetylator status of 200 pulmonary tuberculosis patients was determined by sulphadimidine (SDM) acetylation in (1) urine and (2) serum. In both estimations, distribution of the patients with regard to the acetylation rates was found to be bimodal. Based on the percent frequency distribution of acetylated SDM, the antimode for urine and serum was 65% for the former and 45% for the latter. Patients acetylating above 65% or 45% of administered SDM were taken as rapid acetylators, while those acetylating less, were slow acetylators. The ratio of slow to rapid acetylators in urine and serum was 58 42 and 66 34 respectively. The renal clearance of acetylated fraction of SDM was considerably greater as compared to that of the unacetylated fraction. Agreement between the two methods as evaluated by the kappa statistic was 0.71. The determination of the acetylator status by the SDM acetylation test in the urine is simple to perform and has acceptable accuracy. It may be used as an acceptable substitute to serum for estimating the isoniazid inactivation status which is of considerable importance when patients are treated with daily/ intermittent/once-weekly drug regimens for tuberculosis.