서울중앙병원에서 IMx를 이용한 혈장내 총 Homocysteine의 측정

Abstract

Elevated plasma homocysteine (HCY) levels are considered to be an independent risk factor in coronary atery disease, cerebrovascular disease, and peripheral vascular disease. Currently HPLC fluoremetric detection has been most widely used for the quantitation of homocysteine. Recently IMx homocysteine assay by use of a fluorescence polarization immunoassay(FPIA) has been introduced that enables rapid quantitation ofplasma homocysteine levels. We evaluated the performance of the IMx® Homocysteine assay and compared it to routinely used HPLC method. Within-run precision, between-run precision, degree of correlation, linearity, and reportable ranges were analyzed, according to National Committee for Clinical Laboratory Standards guidelines as much as possible. To establish a reference interval 148 apparently healthy adults were investigated (81 males, 67 females). For the methods comparison We selected 20 patients admitted to the Asan Medical Center. The total plasma homocysteine concentraton was measure by FPIA (lMx®Homocysteine assay, Abbotte Laboratories, IL, USA) and by HPLC (HP1100, Hewlett Packard com., Germany) using Bio-rad® Homocysteine kit (Bio-Rad Laboratories, CA, USA). The caIculations were performed with computer software, EP_Suit(MarChem Associates, Concord, USA). The within run coefficients of variations (CVs) of the low, medium, and of the high control were 1.8%, 1.5% and 1.5%. The between run CVs were 2.8%, 1.4% and 1.0%,respectively. Method was linear and passed lack of fit. Reportable range was found to be 0.5-50.0 μmol⁄L. The reference interval from healthy adults was 10.3±5.54(mean±SD) μmol⁄L. Total plasma homocysteine levels according to sex were 11.9±6.89(mean±SD) μmol⁄L for male, 8.39±2.03(mean±SD) μmol⁄L for female, respectively. The comparison between FPIA (y) and HPLC(x) resulted in a linear regression analysis described by the equation : y=0.9463x-0.2364 with a correlation coefficient r=0.9961. Linearity, pricision, reportable ranges of the IMx homocysteine were satisfactory. The IMx homocysteine also correlated well with HPLC method. The normal range, determined by testing apparently healthy adults, is in agreement with the literature. The IMx homocysteine assay is fast and easy to perform and very useful for routine determinations of plasma homocysteine levels.