title: Accuracy evaluation and hematocrit effect of commercial ionized calcium analyzers using Japanese serum reference material.
abstract: The serum reference material for concentration measurement of ionized calcium in blood has been established by our research group in Japan. The reference method used is the reference standard cell (RSC:IFCC/WGSE, Covington-Umemoto Cell) system. Here we present the results of the evaluation of accuracy using the serum reference material and the hematocrit effect of the nine commercial ionized calcium analyzers being used in routine measurements by Japanese round robin test program. The ionized calcium concentration and pH of two concentration levels of the reference material were analyzed in triplicate measurements according to the standard procedures designated by manufacturers. The effect of hematocrit in ionized calcium concentration measurement was tested using plasma and whole blood with hematocrit values of 35%, 50% and 65%, respectively. The range of bias of ionized calcium values were -0.14 approximately +0.09 mmol/L, -0.12 approximately +0.09 mmol/L for ionized calcium, respectively. The effect of hematocrit in ionized calcium concentration measurement was strongly observed in GEM Premier, CAI-101 and GASTAT-2 analyzers.
authors.affiliation: Department of Clinical Chemistry, College of Medical Technology and Nursing, University of Tsukuba, Ibaraki, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kuwa
authors.forename: W
authors.initials: W
authors.lastname: Tani
authors.forename: K
authors.initials: K
authors.lastname: Hayashi
authors.forename: M
authors.initials: M
authors.lastname: Umemoto
mesh_terms: D002118:Calcium / Q000032:analysis* / Q000097:blood; D005069:Evaluation Studies as Topic; D006400:Hematocrit; D006801:Humans; D007477:Ions; D007564:Japan; D013677:Medical Laboratory Science / Q000295:instrumentation / Q000592:standards*; D012016:Reference Values
chemical_list: D007477:Ions; D002118:Calcium