Hemoglobin determination with point-of-care testing

Abstract

Background: With point-of-care testing, (POCT) we obtain results quickly, reliably and with a minimal amount of sample. We noticed that occasionally hemoglobin Hb results obtained by POCT compared with those obtained by laboratory testing differ significantly, especially the Hb values that are lower or higher than average. Methods: We included 130 samples of capillary and venous blood in our study. With POCT method we determined Hb from both types of samples and with laboratory testing we determined Hb from venous samples. Results: We included 103 samples from blood donors who came to blood donation and 27 samples from patients after major orthopedic surgery. Capillary Hb concentration ranged from 70 to 201 g /L. We found that there was a good correlation between the values obtained with POCT of both, capillary and venous samples (R2 = 0.949). Even more reliable was the determination of Hb from venous samples measured by POCT and laboratory testing (R2 = 0.982). When we compared the average deviations in different groups of Hb concentrations of capillary samples, we found that it was the lowest in the group of middle values (120–140 g /L) where it was -0.4 and higher where the deviation was larger (in the group up to 120 g/L it was 1.2, in the group between 141 and 160 g /L it was -3.6, in the group between 161 to 180 g /L it was -8.6 and in the group over 180 g /L even -14.3). Conclusion: We found that POCT is a suitable method for the determination of Hb, which – when implemented correctly – provides reliable test results for the selection of blood donors and decision making for transfusion. However, the reliability of the results obtained with higher Hb values is smaller, therefore we recommend laboratory testing. When this is not feasible, Hb determination with POCT in a venous blood sample is better than in a capillary one