The use of the autoanalyzer to determine the acetylator phenotype.

It has been pointed out (Rao et al, 1970) that with the advent of intermittent treatment regimens the determination of the acetylator phenotype has become of practical importance. It has recently been shown that rapid acetylators have an inferior response to slow acetylators when their tuberculosis is treated with once weekly treatment regimens (Menon, 1968; Tuberculosis Chemotherapy Centre, Madras, 1970). Sulfamethazine is polymorphically acetylated in man by the same N-acetyl transferase as isoniazid (Evans and White, 1964). The stable storage properties, easy analysis, and speedy availability of results have led to sulfamethazine acetylation being developed as a phenotyping test in preference to isoniazid (Evans and White, 1964; Evans, 1969; Rao et al, 1970). It has been shown that a single small dose of 40 mg sulfamethazine per kg body weight is sufficient (Evans, 1969); and either a single urine specimen (Rao et al, 1970), or alternatively one urine and one serum (or plasma) specimen (Evans, 1969) are required for analysis. The purpose of the present communication is to show that a Technicon AutoAnalyzer can be used to perform the analyses required in the acetylator phenotyping procedure.