Testing of clinical thermometers

Area of Science:

• Medical Device Standards
• Clinical Thermometry
• Quality Assurance

Background:

• Voluntary standards are crucial for medical device safety and efficacy.
• The Food and Drug Administration (FDA) evaluates the applicability of these standards.
• Ensuring clinical thermometers meet established benchmarks is vital for accurate patient temperature readings.

Purpose of the Study:

• To assess the conformity of clinical thermometers to the ANSI/ASTM E 667-79 voluntary standard.
• To determine the feasibility and reasonableness of applying this standard to marketed devices.
• To identify specific areas where clinical thermometers fail to meet standard requirements.

Main Methods:

• Testing of 149 maximum self-registering, mercury-in-glass clinical thermometers from eight manufacturers.
• Adherence to the test methods and requirements outlined in ANSI/ASTM E 667-79.
• Analysis of failure rates based on different criteria, including accuracy and markings.

Main Results:

• 42% of fever thermometers and 100% of basal thermometers failed to meet at least one requirement of the standard.
• Excluding graduation marks and identification requirements, failure rates decreased to 14% for fever and 8% for basal thermometers.
• Thermometers failing accuracy requirements were only slightly out of compliance, by 0.1°F.

Conclusions:

• A significant percentage of clinical thermometers do not fully comply with ANSI/ASTM E 667-79.
• The standard's requirements for markings and identification contribute substantially to failure rates.
• Most clinical thermometers demonstrate acceptable accuracy, with minor deviations when failures occur.