title: Preincubation of serum aspartate aminotransferase with pyridoxal 5'-phosphate in the SMAC: comparison with revised DuPont aca method and recommended IFCC method.
abstract: The method for continuous-flow assay of aspartate aminotransferase with the Technicon SMAC was modified to include preincubation of the serum enzyme with pyridoxal 5'-phosphate, to be consistent with the recommendations of IFCC and the Standards Committee of AACC. Preliminary estimates of the imprecision of the modified method on SMAC gave day-to-day standard deviations of 5.3 U/L at mean of 48 U/L (n = 66) and 6.2 U/L at 155 U/L (n = 61). Added bilirubin, sodium pyruvate, ascorbic acid, and endogenous lipids did not interfere. Comparison of results for 50 samples by this method with those by the manual IFCC method gave y = 1.1113x - 0.3 U/L, Sy/x = 4.4 U/L, and r = 0.997. Similar data are presented for the revised AST method for the DuPont aca discrete analyzer. Clinical data show that AST activities increase by as much as 200% when the serum is preincubated with pyridoxal 5'-phosphate.
mesh_terms: D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood*; D002138:Calibration; D004789:Enzyme Activation; D006801:Humans; D008722:Methods; D011732:Pyridoxal Phosphate / Q000378:metabolism*; D011817:Rabbits
chemical_list: D011732:Pyridoxal Phosphate; D001219:Aspartate Aminotransferases