Evaluation of a Modified Roche Enzymatic Ammonia Method for Roche Cobas 6000 (c501 Module) Automated Platform: When 5 µL Improves Performance.

BACKGROUND

We evaluated a modified Roche NH3L method developed by our group that significantly reduced the error flag "> ABS (> Absorbance)" on the COBAS 6000 (c501 module) automated platform.

METHODS

Our study was finalized to validate the NH3L open method on COBAS 6000 (c501 module) with imprecision and correlation tests. In addition, the NH3L open method was evaluated for determination of lower limit of blank (LoB), lower limit of detection (LoD), and accuracy.

RESULTS

The imprecision test showed good results with CV for all samples tested < 3 and < 5 for within-run and between-run assays. Correlation tests of NH3L classic and NH3L open method showed good correlation with R square = 0.95. "> ABS" obtained with the NH3L open were only 2% compared to NH3L classic method.

CONCLUSIONS

Our study shows that the NH3L open method is reproducible and stable, providing values which correlate with those obtained by the traditional method. The ability to reduce the alarm > ABS by more than 95% thanks to lower background absorbance values makes this method reliable, avoiding re-testing or the need for sample dilutions.