Clinical reference values for laboratory hematology tests calculated using the iterative truncation method with correction: Part 2, Reference values for white blood cell (WBC) count, WBC differential including segmented neutrophil, band neutrophil, lymphocyte, monocyte, eosinophil, basophil, platelet count and mean platelet volume

Age and sex dependent differences in the clinical reference values for white blood cell(WBC) count, WBC differential including segmented neutrophils(SEG), band neutrophils(BAND), lymphocytes (LYMPH), monocytes(MONO), eosinophils(EOSINO), basophils(BASO), platelet count(PLT) and mean platelet volume(MPV) were calculated by the iterative truncation method with correction(Usui's method) using the result from tests on 6,300 patient specimens obtained at Kyoto University Hospital. WBC counts exhibited log-normal distribution in all age either in male and female. PLT counts and MPV showed normal or log-normal distribution. WBC differential (SEG, BAND, LYMPH, MONO, EOSINO, BASO) usually showed log-normal distribution. As to the reference value for WBC, high limit values gradually decreased in the age range of 5-14 year old in males and females. After 15 year old, it gradually increased and reached adult's level. Low limit values for WBC gradually decreased with age both in males and females. The reference value for SEG showed similar change to WBC. The reference value for LYMPH gradually decreased age both in males and females. The reference values for BAND, MONO, EOSINO, BASO were generated by the percentile method instead of the iterative truncation method because of the strong deviation in the distribution pattern. BAND, MONO and BASO values were very stable for all ages in males and females. High limit values for EOSINO in the age range of 5-10 year old in males and females remained constant, and gradually decreased in 10-20 year old, and were stable at ages above 20 year old. PLT counts gradually decreased with age, and the MPV remained constant in all age populations both in male and female.