We evaluated the delta check method for hematologic laboratories to detect specimen mix-up. We selected 271 patients with hematologic disorders and two types of investigation were conducted. The first investigation comprised statistical analysis, while the second involved evaluation of the procedure. From parameters of white blood cell, red blood cell, hemoglobin, hematocrit, mean corpuscular volume(MCV), mean corpuscular hemoglobin(MCH), mean corpuscular hemoglobin concentration(MCHC), and platelets, MCV was considered to represent the best single marker to detect artificial mix-up. About 98% of MCV delta values from one patient were within 3 fl. Conversely, 40% of MCV delta values in artificial mix-ups exceed 10 fl. No correlations between time interval and MCV delta values were detected. However, some cases were observed in which MCV delta values changed markedly over a short period of time even though the samples originated from one patient. In conclusion, we recommend investigation for specimen mix-up in cases where MCV delta values exceed 4 fl.

*1Department of Clinical Laboratory Medicine, Jichi Medical School, Kawachi-gun, Tochigi-pref. 329-0498