Usefulness of biological variation in the establishment of delta check limits.

•A large difference was observed between the nine routine chemistry tests in the percentage exceeding the delta check limits by RCV.•Delta percent changes of the paired test results of protein, albumin, Na, K and Cl showed a symmetric distribution•Delta percent changes of the paired test results of glucose, AST, ALT and creatinine showed an asymmetric distribution•A good correlation was found between CVI and the delta check limits according to population distribution and a closer correlation was observed when using the test items with CVi of <5.0%.