Eva Wittenmeier1, Linda Lesmeister2, Irene Schmidtmann3, Johannes Lotz4, Frank Dette1, Eva Mildenberger5. 1. Abteilung für Klinische Anästhesie, Klinik für Anästhesiologie, Universitätsmedizin Mainz, Mainz. 2. Klinik und Poliklinik für Kinder- und Jugendmedizin, Uniklinik Köln, Köln. 3. Abteilung für Biometrie, Institut für Medizinische Biometrie, Epidemiologie und Informatik, Universitätsmedizin Mainz, Mainz. 4. Institut für Klinische Chemie und Laboratoriumsmedizin, Universitätsmedizin Mainz, Mainz. 5. Sektion Neonatologie, Zentrum für Kinder- und Jugendmedizin, Universitätsmedizin Mainz, Mainz.
Abstract
BACKGROUND: In neonatologic clinical practice and research the percentage of fetal hemoglobin (HbF) of total hemoglobin can be of interest. Blood gas analyzers offer the measurement of HbF. However, it is not known if results are accurate enough to apply in clinical decision-making or scientific questions. In this prospective diagnostic study, we examined the accuracy of HbF measurement by a blood gas analyzer. METHODS: On a neonatal intensive care and neonatal ward, the percentage of HbF was measured using both the laboratory gold standard (HbFlab, reference method) and the blood gas analyzer (HbFgas) (ABL 800 Flex, Radiometer). Agreement of HbFlab and HbFgas was assessed by the Bland-Altman method including bias and limits of agreement and by calculation of the root mean square error (RMSE). RESULTS: Thirty-five measurements in 23 term and preterm infants with a median body weight of 2190 g (min-max 967-3800 g) and a median postmenstrual age of 36+1 weeks (min-max 29+6-43+2) were performed. The Bland-Altman diagram for the measurement of HbF(gas) versus HbF(lab) shows an overestimation of HbF by the blood gas analyzer (bias 9.3%, limits of agreement 1 to 17.6%). RMSE was 10.2%; 45.7% of HbFgas measurements were >10% out of range from HbFlab. There was no influence of age, body temperature or oxygen saturation on the bias (p=0,132; p=0,194; p=0,970), but bias increased with increasing HbFlab (Pearson correlation r=0,426; p=0,011). CONCLUSION: The measurement of HbF in term and preterm infants by a blood gas analyzer lacked sufficient agreement with that of the reference method to recommend this application for clinical decision-making or scientific purposes. Thieme. All rights reserved.
BACKGROUND: In neonatologic clinical practice and research the percentage of fetal hemoglobin (HbF) of total hemoglobin can be of interest. Blood gas analyzers offer the measurement of HbF. However, it is not known if results are accurate enough to apply in clinical decision-making or scientific questions. In this prospective diagnostic study, we examined the accuracy of HbF measurement by a blood gas analyzer. METHODS: On a neonatal intensive care and neonatal ward, the percentage of HbF was measured using both the laboratory gold standard (HbFlab, reference method) and the blood gas analyzer (HbFgas) (ABL 800 Flex, Radiometer). Agreement of HbFlab and HbFgas was assessed by the Bland-Altman method including bias and limits of agreement and by calculation of the root mean square error (RMSE). RESULTS: Thirty-five measurements in 23 term and preterm infants with a median body weight of 2190 g (min-max 967-3800 g) and a median postmenstrual age of 36+1 weeks (min-max 29+6-43+2) were performed. The Bland-Altman diagram for the measurement of HbF(gas) versus HbF(lab) shows an overestimation of HbF by the blood gas analyzer (bias 9.3%, limits of agreement 1 to 17.6%). RMSE was 10.2%; 45.7% of HbFgas measurements were >10% out of range from HbFlab. There was no influence of age, body temperature or oxygen saturation on the bias (p=0,132; p=0,194; p=0,970), but bias increased with increasing HbFlab (Pearson correlation r=0,426; p=0,011). CONCLUSION: The measurement of HbF in term and preterm infants by a blood gas analyzer lacked sufficient agreement with that of the reference method to recommend this application for clinical decision-making or scientific purposes. Thieme. All rights reserved.