A comparative study of micro-ammonia determinations in plasma using two different methods

Two commercially available kits for determining blood ammonia were compared, an enzymatic method requiring a sample volume of 100mul and a nonenzymatic method requiring 1 ml of sample. Calibration curves for both kits were linear to 270 mumol/l, however correlation studies on plasma samples revealed a lack of agreement between methods (r equal to 0.825, Y equal to 0.76X +51). Improved correlation occurs when protein interference is eliminated from the enzymatic procedure. Finally, the nonenzymatic method is modified to accommodate 100 mul of sample and compared to the original method.