Objective: To compare the measurement of haemoglobin concentration ([Hb]) using the HemoCue haemoglobinometer with that using the Coulter STKS haemoglobinometer. Design: Thirty two EDTA samples were taken from neonates. [Hb] was measured in these samples using the HemoCue; the samples were then transferred to the haematology laboratory for [Hb] determination with the Coulter STKS. In addition, [Hb] The standard deviation of the differences of the 82 samples was 3.73 g/l. The limits of agreement of the two methods (mean difference ± 2SD) were −4.8 to +9.8 g/l. Conclusion: With adequate training and monitoring, the HemoCue can be used directly on the neonatal unit for rapid determination of [Hb] to within 7.5 g/l compared with the laboratory Coulter STKS, using much smaller sample volumes. N eonates are more likely to be transfused than any other patients in hospital.1 Anaemia can result from haemorrhage, haemolysis, or failure of erythropoiesis, or be iatrogenic from frequent testing. Sampling may be technically difficult and distressing to the baby and observing parents. When receiving a transfusion, the neonate is vulnerable because of its small size, and exposure to multiple potential donors and metabolic disturbances can occur. 2 At present in our hospital, haemoglobin concentrations ([Hb]) are determined using the Coulter STKS, which measures them photometrically after lysis of the red blood cells and conversion of free Hb into a cyanide-containing compound.3 It requires 200 µl of blood and has an accuracy of 2%.4 Although 200 µl may be sufficient, the haematology department request 500 µl, as the commonest cause of error with the Coulter STKS is with small samples, which then need to be repeated.Previous studies have validated the use of the HemoCue haemoglobinometer (HemoCue Ltd, Sheffield, Yorkshire, UK) for near patient testing of [Hb] in children and fetuses.5-7 It measures [Hb] by converting haemoglobin into haemoglobinazide, and uses agents of relatively low toxicity.8 It provides a result almost immediately with a sample of only 10 µl of blood.We undertook a study to determine whether the HemoCue could be used on the neonatal unit of a district general hospital in preference to the Coulter STKS to measure [Hb], thus reducing iatrogenic anaemia, making sampling easier, and providing a result quickly.
METHOD Principle and operation of the HemoCueThe HemoCue is a device (height 90 mm, width 160 mm, depth 210 mm, weight 250 g) that can be operated using battery or mains electricity. The cuvettes for the HemoCue contain the following dried reactants: sodium desoxylate to haemolyse red blood cells; sodium nitrate to convert haemoglobin into methaemoglobin; sodium azide to convert the methaemoglobin into haemoglobinazide. To prevent decay of these reactants from exposure to the atmosphere, the cuvettes are kept in a sealed container. Whole blood (10 µl) is collected in two cuvettes by capillary action, avoiding the formation of air bubbles. Excess blood is removed from the outside of the cuvette, whic...