ABSTRACT
OBJECTIVE: Adaptation of the Randox Enzymatic Manual UV Ammonia method to be used on the Roche Cobas 6000 (c501) automated analyzer platform. DESIGN AND METHODS: The Randox ammonia reagent was evaluated for precision, linearity, accuracy and interference from hemolysis, icterus and lipemia on the Roche c501 analyzer. Comparison studies were conducted for the Randox reagent between Roche c501, Siemens Vista, Ortho Vitros 250, and Beckman DxC methods. RESULTS: The Randox reagent demonstrates acceptable within-run (L1=65 µmol/L, CV 3.4% L2=168 µmol/L, CV 1.9%) and between-run precision (L1=29 µmol/L, CV 7.3% L2=102 µmol/L, CV 3.0%), Analytical Measurement Range (7-940 µmol/L), and accuracy. The method interference profile is superior for the Randox method (hemolysis index up to 600, icteric index up to 60, lipemic index up to 100) as compared to the Roche method (hemolysis index up to 200, icteric index up to 10, lipemic index up to 50). Comparison was very good between the Randox reagent and two other wet chemistry platforms. CONCLUSIONS: The Randox Enzymatic Manual UV Ammonia reagent is an available alternative to the Roche Cobas c501 reagent. The method is more robust to endogenous interferences and less prone to instrument error flags, thus allowing the majority of clinical specimens to be reported without additional sample handling at our institution.
