Clinical acceptance of a multi-test reference region for biochemical-panel results

Results of a panel of six biochemical tests on a patient's specimen were mathematically combined into a "six-test signal strength" (STSS) value. This value indicated the overall extent of change from physiological results, and it was calculated in a way that ensured that a STSS value less than or equal to 1 occurred in 95% of apparently healthy people. STSS was reported with the test results for hospital inpatients during a four-month trial period. Doctors requested a repeat of the panel less often when a low STSS was reported, even if some test results were outside their separate reference intervals. Clinicians expressed differing opinions about its usefulness, some finding that a high STSS value had saved them from overlooking abnormal results, others not finding the value to be any practical advantage. Using a multi-test normal region resolves a statistical dilemma, while compounding the problem of knowing what results really mean.