Evidence for the use of the Alere Afinion™ AS100 for measuring the levels of C-reactive protein in an elderly South African population

Abstract

Introduction: This study evaluated the performance of the Alere Afinion™ AS100 analyser for the measurement of C-reactive protein (CRP) levels in a population of older adults from South Africa. Methods: This study was a sub-study of the Sexual Health, HIV infection and comorbidity with non-communicable diseases among Older Persons (SHIOP) study. The median age of SHIOP participants was 61 years (interquartile range 12). Serum samples collected through SHIOP were used to measure CRP levels on the Alere Afinion™ AS100 (Point-of-care) and ABX Pentra 400 (reference method), respectively. Bland–Altman analysis and Lin’s concordance correlation coefficients were used to assess the agreement between the two analysers. Results: A total of 183 serum samples were tested in the study. The Alere Afinion™ AS100 median values for CRP were 9.5 mg/L and 11.5 mg/L in women and men respectively (p = 0.275). The ABX Pentra 400 median levels were lower with 5.6 mg/L and 3.6 mg/L for women and men (p = 0.027), respectively. Bland–Altman analysis and linear regression analysis showed an excellent correlation between the Pentra and Afinion analysers, with a Lin’s concordance correlation coefficient of 0.971. The Alere Afinion™ AS100 was able to correctly classify > 90% (165/183) of the CRP results when compared to the ABX Pentra 400. Conclusion: This study showed that the Alere Afinion™ AS100 had an excellent correlation with a standard laboratory method. However, the Afinion™ AS100 did not correlate well at elevated CRP levels. This may not be clinically significant since the cut-points for CVD risk are at much lower levels.