Correlation between hemoglobin and hematocrit results obtained on full blood count and blood gas analysis in children

Introduction: The hematocrit (Hct) and hemoglobin (Hb) values are routinely used in hospitals to monitor the evolution of the patient's health status and are the basis for clinical management. Both can be measured by the laboratory tests of blood gas analysis and complete blood count; however, the scientific literature on the equivalence between these results is controversial. Objectives: The present study compared the results of Hct and Hb from laboratory autoanalyzer and blood gas analyzer of a clinical laboratory of a high complexity pediatric hospital in Brazil and evaluated the correlation between them. Materials and methods: Results were collected from 2263 patients aged zero to 18 years who have simultaneous blood samples taken for full blood count and blood gas analysis over six months. For statistical calculations, patients were divided into children under 30 days, between 31-180 days, 180 days-2 years, and 2-18 years. Results: The results revealed a difference between the Hct and Hb results obtained by the different devices. Although a strong positive correlation between these results has been demonstrated in most age groups, children over two years had only a moderate correlation for Hb levels. Conclusion: Considering that such differences can result in changes in clinical and therapeutic management, it has been concluded that the alternate use of these methods is not recommended in the monitoring of pediatric patients unless a proper correction factor is determined and adopted to minimize methodological differences.