The determination of calcium, glucose, urea and uric acid using the Kodak EKTACHEM multilayer film technology: an evaluation.

Calcium, glucose, urea and uric acid determinations on the "'Kodak Ektachem Four Chemistry Analyzer" were tested for precision and an estimation of the accuracy was performed with our laboratory routine methods using patients' sera and proficiency fluids. Precision -- examined over a period of six weeks -- was very good. Even the very stringent claim of the College of American Pathologists (CAP) -- that analytical dispersion should be less than 1/16th of the normal range -- was fulfilled in almost all control samples. The results from patients' sera measured using both the Ektachem and the routine laboratory methods showed very good correlation. Proficiency fluids tested for calcium, glucose and uric acid all resulted in values well within the assigned interval. Some negative bias was noted for the urea determination however. This could not be completely eliminated even though the samples had been reconstituted with a bicarbonate solution according to the manufacturer's instructions. The linear range of the four determinations was checked: calcium is linear up to 4.2 mmol/l, glucose up to 33 mmol/l, urea up to 60 mmol/l and uric acid up to 1370 mumol/l. Our results confirmed the long-term stability of analyzer and slides to be so high that one calibration per week is sufficient.