Assessment of haemoglobin measurement by several methods – blood gas analyser, capillary and venous HemoCue®, non-invasive spectrophotometry and laboratory assay – in term and preterm infants

Abstract

A laboratory haematology analyser is the gold standard for measuring haemoglobin concentration but has disadvantages, especially in neonates. This study compared alternative blood-sparing and non-invasive methods of haemoglobin concentration measurement with the gold standard. Haemoglobin concentrations were measured using a laboratory haematology analyser (reference method), blood gas analyser, HemoCue® using venous and capillary blood samples and a newly developed non-invasive sensor for neonates < 3 kg. A total of 63 measurements were performed. Body weight (2190 (1820–2520 [967–4450]) g) and haemoglobin concentration (12.3 (10.6–15.2 [8.2–20.5]) g.dl−1) varied widely. Bias/limits of agreement between the alternative methods and reference method were −0.1/−1.2 to 1.0 g.dl−1 (blood gas analyser), −0.4/−1.8 to 1.1 g.dl−1 (HemoCue, venous blood), 0.7/−1.9 to 3.2 g.dl−1 (HemoCue, capillary blood) and −1.2/−4.3 to 2 g.dl−1 (non-invasive haemoglobin measurement). Perfusion index, body weight and fetal haemoglobin concentration did not affect the accuracy of the alternative measurement methods, and these were successfully applied in term and preterm infants. However, the accuracies of non-invasive haemoglobin measurement and HemoCue of capillary blood especially lacked sufficient agreement with that of the reference method to recommend these methods for clinical decision making.