[Evaluation of biochemical results]

Reference intervals (RI) are used to evaluate biochemical results in diagnosis. In monitoring the critical difference (KF) should be preferred, as the biological within-person variation divided by the between-person variation for biochemical quantities often is less-than 0,6, meaning that results may change without exceeding the limits of RI. The personal RI is a variant of KF. It uses the same terminology as conventional RI, but is less flexible than KF. This review finds that IT systems for evaluating analytical results should consider the shortcomings of RI and offer the availability of KF.