Delta Checks for Random Error Detection in Hematology Tests

We developed a computerized algorithm for real-time hematology delta checks, comparisons between current and previous patient automated blood cell counts. Delta checking is restricted to an arbitrarily set maximum of seven days and uses linear as well as variable-rate nonlinear discriminant functions.Two delta levels were used–one for intralaboratory use and one requiring interaction with the referring unit or physician. The delta checks are useful for (1) random error detection mainly using a combination of two RBC parameters, mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH), that remain stable over time; (2) warning for significant clinical changes in hemoglobin, MCV, WBC, and/or platelets; and (3) the elimination of manual checks on abnormal RBC morphology, WBC counts, and for platelet counts in specimens with repeatedly abnormal values.