Evaluation of BNP Assays with Access 2 and AxSYM BNP in Comparison with Point-of-Care Triage BNP assay

Kang, So Young; Suh, Jin Tae; Kim, Myung Hee; Lee, Woo In; Lee, Hee Joo

Abstract

BACKGROUND
B-type natriuretic peptide (BNP) is a sensitive and specific marker used widely for the detection of ventricular disorder such as congestive heart failure (CHF). Recently, the manufacturer of Triage BNP assay has developed the liquid type BNP reagent for the usage on the Beckman Coulter Immunoassay Systems such as Access 2. We performed comparison study between Triage BNP assay, Access 2 Triage BNP assay, and AxSYM BNP assay. METHODS: The precision study of Access 2 Triage BNP and AxSYM BNP was performed with 5 levels of pooled plasma from 10 to 2, 000 ng/L. The correlation study of Access 2 Triage BNP and AxSYM BNP with Triage BNP assay was done by regression analysis and Bland-Altman analysis with 110 patient samples. The patients were classified and compared using medical decision value of 100 ng/L and final diagnosis. RESULTS: The within-day coefficients of variation (CVs) of Access 2 Triage BNP and AxSYM BNP were less than 10% in all levels of pooled plasma. Both of Access 2 Triage BNP (y=0.93x+0.17, r= 0.95) and AxSYM BNP (y=1.09x+7.6, r=0.97) showed good correlation with Triage BNP assay. Bland Altman analysis revealed that the difference was increased in proportion to BNP concentration in high concentration. However, the discrepancy of classification of patients was less than 8% when patients were classified with medical decision level of 100 ng/L. In the comparison of BNP levels among different disease groups, CHF group showed significantly higher BNP levels than angina and other disease groups. CONCLUSIONS: The Access 2 Triage BNP and AxSYM BNP were showed reliable performance and comparable result with Triage BNP assay. However, the discrepant result found in high concentration should be improved by standardization between different assay methods or instruments.