Tadashi Hoshino, Yasuhiro Sakai, Kazuaki Yamashita, Kouji Kishi, Katsuhisa Tanjoh, Atsushi Hirayama, Tomohiro Nakayama
Division ofLaboratory Medicine, Department of Pathology and Microbiology, Nihon University School ofMedicine, Tokyo, Japan.
Clinical laboratory 2013Measuring creatine kinase (CK) MB activity using the immunoinhibition method remains useful in clinical laboratories. CK-MB activity is abnormally high when macro CK type 2 (mitochondrial creatine kinase, MtCK) is present in patient serum. In order to improve the accuracy of the CK-MB activity assay, we developed a new CK-MB activity method using highly specific anti-MtCK antibodies. We evaluated the clinical performance of the new method, which abrogates the effect of MtCK activity. Receiver operating characteristic analysis, CK-MB activity range, cut-off, and CK-MB to CK activity ratio were investigated. Mean CK-MB activity in normal human serum was 2.5 U/L by our method, in contrast to 12.0 U/L by the current method. Approximately 80% of CK-MB activity determined using the current kit corresponds to MtCK activity, and ubiquitous mitochondrial creatine kinase activity constitutes approximately 90% of MtCK activity. The cut-off and CK-MB activity ratio of our method were 12 U/L and 3 to 20%, respectively, in contrast to 22 U/L and 5 to 23%, respectively, using the current CK-MB method. The areas under the curve of our method, current CK-MB, electrophoresis, and CK-MB mass were 0.976, 0.928, 0.967, and 0.991, respectively. Our new method was superior to the electrophoresis and CK-MB mass as well as the conventional method due to jts promptness, simplification, and low cost. The new kit will improve the clinical diagnosis of acute myocardial infarction. CK-MB activity assay was considered as a suitable alternative to conventional cardiac markers due to its superior diagnostic validity.
Tadashi Hoshino, Yasuhiro Sakai, Kazuaki Yamashita, Kouji Kishi, Katsuhisa Tanjoh, Atsushi Hirayama, Tomohiro Nakayama. Clinical evaluation of a new creatine kinase MB activity reagent abrogating the effect of mitochondrial creatine kinase. Clinical laboratory. 2013;59(3-4):307-16
PMID: 23724619
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