Hemoglobin determination with point-of-care testing, performance evaluation compared to central laboratory analyzers in transfusion decision, an in vitro and retrospective study

Abstract

Introduction: Point of care (POC) analyzers are an integral part of the patient care. Transfuse can be an emergency decision, not being a benign act, it is necessary to ensure that the hemoglobin value measured by the POC are comparable with the reference analyzer. The objective is to compare the analytical performance of three POCs: ABL800 Flex, Hemocue and iSTAT and a central laboratory analyzer: XN-10 and the impact on the transfusion decision.

Methods: An in vitro study was performed in 50 patients for whom a hemogram had been prescribed on the XN-10, the hemoglobin determination was performed in parallel on the three POCs. Then, retrospective study was performed to compare the hemoglobin values returned for matched samples in routine practice, 5505 for ABL800 Flex, 55 for Hemocue and 70 for iSTAT were analyzed.

Results: In vitro study shows systematic biases in the measurement of hemoglobin between the different analyzers, overestimation for the ABL800 Flex and the Hemocue, underestimation for the iSTAT. These biases are accentuated in current practice for iSTAT but decreased for ABL800 Flex. In the transfusion decision range from 70 to 100 g/L, there were 8.6% of clinically discordant results between the reference method and ABL, 34.8% for Hemocue and 21.4% for iSTAT.

Conclusion: In addition to systematic biases, many additional factors may be involved for variation in hemoglobin measurement with POC. Thus, in the case of urgent transfusion decisions, sending a hemogram on a central laboratory analyzer seems to be essential, while being compatible with a life-threatening emergency.

Keywords: hemoglobin; point-of-care; transfusion threshold.