Delta check tables for the Technicon SMA 6 continuous-flow analyzer.

To provide a data base for the establishment of a method to detect potentially incorrect SMA 6 test results, we analyzed 2970 pairs of SMA 6 results. For each test result, as well as for the urea nitrogen/creatinine ratio and the anion gap, we estimated to probability density function of the amount of change since the most recent test of the same type. We made separate estimates for each of three ranges of the current test result and two ranges of time-spacing between the tests. Tables of nonparametric estimates of selected points from each of the six distributions for each test result and calculated quantity were developed. These tables could be used to identify unlikely test results, either manually or with a laboratory computer.