Characteristics and performance evaluation of the Maastricht room calorimeter systems

The objective was to describe the characteristics and evaluate the performance of four room calorimeters (RCs) at the Metabolic Research Unit Maastricht in line with the RICORS1.0 standards. The study involved technical assessment and performance evaluation of four identical RCs through three different tests: zero tests (to assess drift and bias), methanol combustion (to assess system performance), and gas infusion protocols (to assess system performance and to determine response time under simulated metabolic conditions). Data were analysed at one-minute and five-minute intervals. All RCs demonstrated minimal bias and drift, with zero test standard deviations within expected ranges (VO₂: <20 ml min^-1, VCO₂: <5 ml min^-1). Methanol combustion tests showed errors below 5% for VO₂, VCO₂, and energy expenditure, with consistent results for 8 h and 24 h durations. Response times ranged from 8 to 12 min with one-minute data and from 15 to 20 min with five-minute averages. Five-minute averaging reduced variability without compromizing accuracy. The RCs in Maastricht meet RICORS1.0 performance standards, with high accuracy and reliability. Shorter-duration combustion tests and five-minute data averaging offer practical advantages without reducing data quality. These findings support their application in diverse human metabolic research settings.