Comparison of noninvasive and invasive point-of-care testing methods with reference method for hemoglobin measurement

Rapid and practical point-of-care testing (POCT) devices become more popular, especially in blood donation centers for determining predonation hemoglobin (Hb) concentrations. The purpose of this study was to evaluate accordance between the POCT methods and the venous method as the reference to Hb screening.

A total of 353 subjects with no known significant health problems were included in the study. Hb screening was performed by two different POCT methods, a noninvasive method (Haemospect, MBR, Germany) and an invasive method (HemoControl, EKF Diagnostic, Germany), and a venous method as the reference (Sysmex XE-2100, Sysmex Europe, Germany). The obtained results were compared.

The sensitivity and the specificity values of the invasive POCT method (83.3%, 87.9%) were higher than the noninvasive POCT method (66.7%, 77.1%). The Bland-Altman analysis was evaluated for both sexes and the bias of the noninvasive POCT method of the males (-0.97 g/dL) was higher than the bias of the invasive POCT method of the males (-0.07 g/dL). We found a better correlation between the invasive POCT method (r = .908) compared with the venous method than the noninvasive POCT method (r = .634).

Predonation Hb measurements must be performed with accurate, precise, and practical methods. Although the noninvasive POCT method was practical and painless, it had lower levels of specificity and sensitivity, and more false deferral and pass rates than the invasive POCT method. The POCT methods agreeable to the venous method as the reference might be suitable for Hb screening especially for centers of excessive numbers of blood donation.