Evaluation of Radiometer ICA1 as a routine instrument for serum ionized calcium and its application for whole blood capillary samples from newborn infants

Publisher Website
Google Scholar
Abstract
The Radiometer ICA1 was evaluated with four sets of samples: a) 289 serum samples sent for routine analysis of ionized calcium, b) a reference set of serum samples from 40 healthy laboratory workers, c) 42 capillary whole blood samples from healthy full-term and d) six capillary whole blood samples from pre-term infants. For comparison, all sets except the capillary samples were also run on the Orion SS-20. The ICA1 gave higher readings than the Orion SS-20 for normo-(mean difference 0.011 mmol/1) and hypocalcaemic (mean difference 0.037 mmol/1), but not for hypercalcaemic serum samples. The mean ± 2 SD range for the serum reference set was 1.15–1.31 mmol/1 for ICA1 and 1.14–1.27 mmol/1 for Orion SS-20. The within-assay and between-assay precision were 0.014 and 0.032 mmol/1 (SD) respectively for ICA1 and 0.010 and 0.022 mmol/1 (SD) for Orion SS-20. The 42 healthy full-term infants had a mean ± 2 SD range of 1.18–1.47 mmol/1. The six pre-term infants had whole blood ionized calcium 0.82–1.07 mmol/1. Three of them had ionized calcium <0.90 mmol/1 and a symptomatic hypocalaemia.