Evaluation of the Beckman Creatinine Analyzer 2.

The Beckman Creatinine Analyzer 2 was evaluated in our laboratory. This new instrument determines creatinine by a Jaffe rate method and utilizes an optical detection system which measures the rate of change in absorbance at 520 nm 25.6 seconds after sample introduction. The linearity of the instrument was verified up to creatinine concentrations of 24 mg/dl. Recovery averaged 92% from serum and 97% from urine. Comparison studies using serum specimens were made against a manual, non-kinetic Jaffe method and a Technicon SMA 12/60. Urine comparisons were made against the manual method. All comparisons indicate the Beckman analyzer yields lower creatinine values due to the minimization of interferences from non-creatinine chromogens. No significant change in these correlations was observed with elevated bilirubin concentrations (greater than 10 mg/dl) or with lipemic specimens (triglycerides up to 3390 mg/dl). Both within-day and day-to-day precision were shown to be within the stated manufacturer's specifications for both sera and urine specimens.