Calibration of a hand‐held haemoglobin analyser for use on fish blood

The HemoCue haemoglobin analyser consistently overestimated haemoglobin concentration ([Hb]) in the blood of all fish species (sockeye salmon Oncorhynchus nerka , Chinook salmon Oncorhynchus tshawytscha , Pacific bluefin tuna Thunnus orientalis and chub mackerel Scomber japonicus ) by 22–50% (9·9–36·0 g l −1 ) over a [Hb] range of 20–160 g l −1 . The systematic nature of the overestimation, however, allowed the formulation of an accurate calibration equation that can be used to correct values of [Hb] measured by the HemoCue in field studies.