Autor:innen:
R. Dolscheid-Pommerich (Bonn, DE)
S. Verlage (Köln, DE)
B. Stoffel-Wagner (Bonn, DE)
I. Gräff (Bonn, DE)
Introduction
Determination of hemoglobin (Hb) concentration with either POCT co-oximetry or central laboratory SLS detection is critical regarding diagnosis of anemia or critical transfusion limits. At the emergency department of the University Hospital Bonn (UKB), blood gas analysis, including co-oximetry, is performed during a patient’s first medical examination. At the same time, venous blood is taken and immediately sent via pneumatic tube for further analysis, including blood cell count, to the central laboratory (CL). Given the importance of properly determining hemoglobin concentrations for diagnosing anemia, it is essential to know whether the two methods yield comparable results and whether both are equally appropriate for different age groups. In the present study, we examined this question using a large-scale sample.
Methods
N = 19182 patients were included (10439 male, 8743 female, mean age: 57.4 years, min 18, max 102 years). The cohort of patients was divided into the following three subgroups: 1 (age > 18-64 years, n = 11201), 2 (65-84 years, n = 6500) and 3 (age > 85 years, n = 1481). For each patient, POCT Hb concentration (RapidLab 1265, Siemens Healthineers) and CL concentration (XN1000, Sysmex) were compared. The whole collective as well as the subgroups were analyzed regarding diagnosis of anemia, according to the WHO definition, and critical anemia (Hb < 8 g/dl).
Results
Overall, a significant correlation was found for Hb concentrations between both methods, r = .96, p < 0.001. There were significant differences between the two methods, with POCT yielding higher Hb concentrations (average value: 13.43 g/dl, SD ± 2.41) than CL (average value, 13.1 g/dl SD ± 2.35), p < 0.001. For the whole sample, both methods differed significantly in their classification of anemia according to WHO (male p < 0.001, female p < 0.001) and critical anemia (p < 0.001). In the three subgroups, classification of anemia differed for all age groups (1: male p < 0.001, female p < 0.001, 2: male p < 0.001, female p < 0.001, 3: male p < 0.001, female p < 0.001). Regarding classification of critical anemia, the two methods differed depending on age group. For subgroups 1 and 2, POCT and CL Hb concentrations differed significantly in their classification of critical anemia (1: p = 0.025, 2: p = 0.025), while for subgroup 3, there was no significant difference between both methods used (3: p = 0.054).
Conclusion
Overall, POCT and CL values were highly correlated, however, both methods also yielded relevant differences concerning diagnosis of anemia. Hemoglobin concentrations determined with SLS CL are more likely to yield a diagnosis of anemia compared to Hb determined with POCT co-oximetry at UKB.