title: A rapid method for plasma ammonia estimation using an indigenously purified enzyme.
abstract: Determination of ammonia level in blood is important, especially in the diagnosis of hepatic disorders. An indigenously purified enzyme was used in the standardisation of the assay. The assay is a two reagent system, requires five minutes for completion and can be performed at temperature between 25-27°C. Performance of the assay was assessed by linearity, imprecision, functional sensitivity and interference studies. Lyophilised reagent I and reagent II were found stable for at least one year. The plasma level of ammonia for the controls was 13.7±7.3 μMol/L, whereas for subjects of hepatic disorders, it was 69.1±32.4 μMol/L (P<0.001). The functional sensitivity was between 2-1000 μMol/L. Within-run coefficient of variation was between 1.1-2.0% and between-run coefficient of variation was between 1.9-3.7%. The mean recovery after dilution was 99.6%. The present method can estimate ammonia up to 1000 μMol/L without dilution of sample. Assay time of five minute may be shortened to one minute. This method is suited for routine clinical use in treatment of hepatic disorders.
authors.affiliation: Centre for Biochemical Technology, Mall Road, 110007 Delhi.
authors.forename: M A
authors.initials: MA
authors.lastname: Qadar Pasha
authors.forename: R B
authors.initials: RB
authors.lastname: Ram
authors.forename: M D
authors.initials: MD
authors.lastname: Gupta
keywords: Ammonia; deaminase inhibitor; enzymatic assay; glutamate dehydrogenase