Method Comparison for Total Plasma Homocysteine between the Abbott IMx Analyzer and an HPLC Assay with Internal Standardization
1999; American Association for Clinical Chemistry; Volume: 45; Issue: 1 Linguagem: Inglês
10.1093/clinchem/45.1.152
ISSN1530-8561
AutoresChristine M Pfeiffer, D B Twite, Jessie Shih, Shelley Holets-McCormack, Elaine W. Gunter,
Tópico(s)Esophageal and GI Pathology
ResumoThe increasing interest in measuring total homocysteine in plasma has led to the development of several different methods (1). Although most publications describe HPLC methods with manual sample preparation, the first fully or partially automated kits were introduced recently: a fluorescence polarization immunoassay on the IMx® analyzer (Abbott Laboratories, Abbott Park, IL), a microtiter plate enzyme immunoassay (Bio-Rad Laboratories), and an HPLC kit with electrochemical detection (BAS). We evaluated the Abbott IMx analyzer automated method for total homocysteine and compared it with our HPLC assay with internal standardization. The “Abbott Homocysteine (HCY) assay” is a fluorescence polarization immunoassay based on the highly selective enzymatic conversion of homocysteine to S -adenosyl-l-homocysteine, which is then recognized by a monoclonal antibody (2). The assay requires 50 μL of sample, with no sample pretreatment. A batch of 20 samples can be processed within 1 h. We assessed the intra- and interassay variability, the recovery of added homocysteine, the analytical sensitivity, the stability of the calibration curve, the specificity, and the cross-reactivity towards other thiols. EDTA plasma samples were obtained within a maximum of 30 min after blood collection. Serum samples were obtained from whole blood allowed to clot at room temperature for 30–60 min. Blood specimens were collected by the Emory University Hospital Blood Collection Service under an agreement with the Centers for Disease Control and Prevention (including an omnibus informed consent and Human Subjects Review protocol). All serum and plasma samples were stored at −70 °C. We sequentially analyzed 20 replicates (one carousel) of each of the three serum-based quality-control (QC) pools supplied by Abbott to assess intraassay imprecision …
Referência(s)