Reliability and validity of electrothermometers and associated thermocouples.

OBJECTIVE Examine thermocouple model uncertainty (reliability+validity). DESIGN First, a 3x3 repeated measures design with independent variables electrothermometers and thermocouple model. Second, a 1x3 repeated measures design with independent variable subprobe. INTERVENTION Three electrothermometers, 3 thermocouple models, a multi-sensor probe and a mercury thermometer measured a stable water bath. MAIN OUTCOME MEASURES Temperature and absolute temperature differences between thermocouples and a mercury thermometer. RESULTS Thermocouple uncertainty was greater than manufactures'claims. For all thermocouple models, validity and reliability were better in the Iso-Themex than the Datalogger, but there were no practical differences between models within an electrothermometers. Validity of multi-sensor probes and thermocouples within a probe were not different but were greater than manufacturers'claims. Reliability of multiprobes and thermocouples within a probe were within manufacturers claims. CONCLUSION Thermocouple models vary in reliability and validity. Scientists should test and report the uncertainty of their equipment rather than depending on manufactures' claims.