IDEXX VetTest Chemistry Analyzer. Lawrence A. Dwyer, Ph.D. January 2000 Senior Scientist

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1 Performance of IDEXX VetTest Chemistry Analyzer Lawrence A. Dwyer, Ph.D. January 2 Senior Scientist IDEXX Laboratories, Inc.

2 The Evaluation Objective: To correlate accuracy and precision of the IDEXX VetTest Chemistry Analyzer with a nationally recognized reference standard, the VITROS 2 Chemistry Analyzer from Ortho-Clinical Diagnostics, a Johnson & Johnson company. Design: Canine, feline, and equine serum samples were tested. Samples were chosen to cover the entire dynamic range of individual chemistry tests. Procedure: Patient samples were analyzed on three VetTest Chemistry Analyzers and in duplicate on one Vitros 2 Chemistry Analyzer for 21 different chemistries. Results: A high degree of correlation was observed for all chemistries between the VITROS 2 Chemistry Analyzer and the IDEXX VetTest Chemistry Analyzer. Correlation coefficients ranged from.931 to.999. Clinical Implications: The IDEXX VetTest Chemistry Analyzer is used to perform clinical chemistry analyses in a timely manner. It is important that such technologies meet basic reference methodology standards. By comparing the VetTest Chemistry Analyzer s results to those of the VITROS 2 Chemistry Analyzer, which is referenced against the International Federation of Clinical Chemistry (IFCC), National Committee for Clinical Laboratory Standards (NCCLS), and the Center for Disease Control (CDC) recommended and/or approved methods, VetTest Chemistry Analyzer accuracy has been established. Inside the VetTest Chemistry Analyzer Slide: Spreading layer Filters sample to minimize interference from lipemic, icteric and hemolyzed samples. Support layer Reagent/Registration layer Chemical reaction takes place here Dry Slide Technology: Dry slide technology offers several advantages. The dry slide is made of layers which help to minimize interferences from lipemic, icteric and hemolyzed samples. Dry slides are easier to use, have less user variability, and are more economical than liquid reagent analyzers. Both the Vitros 2 Chemistry Analyzer and the VetTest Chemistry Analyzer utilize dry slide methodology. Chemistries are processed by either endpoint or rate protocols. VITROS is a registered trademark of Ortho-Clinical Diagnostics, a Johnson & Johnson Company.

3 The Comparison Materials and Methods: Canine, feline, and equine serum samples were evaluated on both the Vitros 2 Chemistry Analyzer and the VetTest Chemistry Analyzer according to the applicable users guides. Samples were run on three VetTest Chemistry Analyzers and in duplicate on one Vitros 2 Chemistry Analyzer. Data was collected and plotted on graphs to determine slope, y-intercept and correlation coefficient. Results: The IDEXX VetTest Chemistry Analyzer has a high degree of correlation for each of the 21 chemistries identified below when compared with the Vitros 2 Chemistry Analyzer. Below are correlation graphs for individual chemistries showing slope, y-intercept, correlation coefficient, and number of samples (n). ALB VetTest (g/dl) VITROS 2 (g/dl) Slope=.94 Intercept=.1 Corr. Coeff.=.96 n=186 BUN VITROS 2 (mg/dl) Slope=1.1 Intercept=. Corr.Coeff.=.998 n=113 ALKP Ca Slope=.97 Intercept=11 Corr.Coeff.=.961 n= Slope=.9 Intercept=-.3 Corr.Coeff.=.977 n= VITROS 2 (U/L) VITROS 2 (mg/dl) ALT VITROS 2 (U/L) Slope=1.4 Intercept= Corr.Coeff.=.989 n=88 CHOL VITROS 2 (mg/dl) Slope=.99 Intercept=1 Corr.Coeff.=.996 n=144 AMYL VITROS 2 (U/L) Slope=1.7 Intercept=-3 Corr.Coeff.=.948 n=121 CK VITROS 2 (U/L) Slope=1.3 Intercept=3 Corr. Coeff.=.991 n=97 AST VITROS 2 (U/L) Slope=.99 Intercept=14 Corr. Coeff.=.97 n=8 CREA VITROS 2 (mg/dl) Slope=1.1 Intercept=.1 Corr.Coeff.=.987 n=82

4 GGT VITROS 2 (U/L) Slope=1.1 Intercept=3 Corr.Coeff.=.987 n=87 PHOS VITROS 2 (mg/dl) Slope=1.4 Intercept=-.1 Corr.Coeff.=.992 n=97 GLU VITROS 2 (mg/dl) Slope=1.1 Intercept=1 Corr.Coeff.=.996 n=99 TBIL VITROS 2 (mg/dl) Slope=1.1 Intercept=. Corr.Coeff.=.996 n=9 LDH VITROS 2 (U/L) Slope=1. Intercept=-3 Corr.Coeff.=.992 n=94 TP VetTest (g/dl) VITROS 2 (g/dl) Slope=.97 Intercept=.7 Corr. Coeff.=.931 n=96 LIPA VITROS 2 (U/L) Slope=.9 Intercept=9 Corr.Coeff.=.967 n=74 TRIG VITROS 2 (mg/dl) Slope=.98 Intercept=4 Corr. Coeff.=.92 n=112 Mg 2+ URIC VITROS 2 (mg/dl) Slope=.96 Intercept=.4 Corr. Coeff.=.989 n= VITROS 2 (mg/dl) Slope=1. Intercept=. Corr.Coeff.=.999 n=99 NH 3 1 VetTest (umol/l) Slope=1.11 Intercept=-18 Corr.Coeff.=.99 n= VITROS 2 (umol/l)

5 precision data Methods: The precision data was generated by using control fluids of known concentrations. Two analyses were completed each day (morning and afternoon) for five days. Each of the twenty-one chemistries were run in triplicate. Mean, Within Day Standard Deviation (SD), Total Standard Deviation (SD), and Overall Coefficient of Variation (%CV) were calculated based on this data. (Kringle, R.O. and Bogovich, M.: Statistical Procedures, in Burtis, C.A., and Ashwood, E.R. (eds): Tietz Textbook of Clinical Chemistry, 3rd Ed., pp (1999). Results and Conclusions: The following table summarizes the precision data on an IDEXX VetTest Chemistry Analyzer. The results show excellent precision at all concentrations for each chemistry. Within Total Total Chemistry Mean Day SD SD %CV ALB AlkP ALT Amyl AST BUN Ca Chol CK Crea GGT Within Total Total Chemistry Mean Day SD SD %CV Glu LDH Lipa Mg NH Phos TBil TP Trig Uric Standard Deviation (SD) is the measure of how much the individual values vary around the average (mean). Coefficient of Variation (%CV) is the relative measure of variability. %CV = SD/Mean.

6 Conclusion The IDEXX VetTest Chemistry Analyzer provides accurate and consistent results as compared to nationally recognized standards, the International Federation of Clinical Chemistry, (IFCC), National Committee for Clinical Laboratory Standards, (NCCLS) and the Center for Disease Control (CDC). The IDEXX VetTest Chemistry Analyzer provides unmatched diagnostic decision support for in-clinic analysis. For more information call IDEXX Laboratories, Inc