Temperature measurement reliability and validity with thermocouple extension leads or changing lead temperature.

CONTEXT: Thermocouples' leads are often too short, necessitating the use of an extension lead. OBJECTIVE: To determine if temperature measures were influenced by extension-lead use or lead temperature changes. DESIGN: Descriptive laboratory study. SETTING: Laboratory. OTHER PARTICIPANTS: Experiment 1: 10 IT-21 thermocouples and 5 extension leads. Experiment 2: 5 IT-21 and PT-6 thermocouples. METHODS: In experiment 1, temperature data were collected on 10 IT-21 thermocouples in a stable water bath with and without extension leads. In experiment 2, temperature data were collected on 5 IT-21 and PT-6 thermocouples in a stable water bath before, during, and after ice-pack application to extension leads. RESULTS: In experiment 1, extension leads did not influence IT-21 validity (P  =  .45) or reliability (P  =  .10). In experiment 2, postapplication IT-21 temperatures were greater than preapplication and application measures (P < .05). CONCLUSIONS: Extension leads had no influence on temperature measures. Ice application to leads may increase measurement error.