The reliability of the i-STAT clinical portable analyser

SummaryThe purpose of this investigation was to assess the reliability of the i-STAT clinical portable analyser and CG4+ cartridge measures of blood pH, partial pressures of O2 (pO2) and CO2 (pCO2), bicarbonate ([HCO3−]), base excess (BE), total carbon dioxide (TCO2), oxygen saturation (sO2) and blood lactate ([BLa−]) at various exercise intensities. A comparison between [BLa−] measured by the i-STAT and the Accusport lactate analysers during an intermittent treadmill run was also undertaken. The technical error of measurement (TEM%) at rest, at moderate (200 W) and maximal exercise (V˙O2 max) was acceptable (<15%) for all parameters. The intra-class correlation coefficients for each analyte ranged from weak-to-strong across resting (ICC = 0.19–0.96) and moderate (ICC = 0.30–0.96) exercise intensities. The ICC for all analytes were observed to be strong following maximal intensity exercise (ICC = 0.77–0.95). The comparison of the [BLa−] measures between the i-STAT and Accusport showed that the difference between measures was acceptable at both low (<4 mmol L−1) (−0.39 ± 0.27 mmol L−1), moderate to high concentrations (>4 mmol L−1) (0.58 ± 1.22 mmol L−1), and across all [BLa−] data (0.36 ± 1.13 mmol L−1). In conclusion, the i-STAT clinical analyser and CG4+ cartridge provides reliable measures of a number of blood parameters across exercise intensities. The [BLa−] measures from the i-STAT analyser are consistent with that of the Accusport lactate analyser.