Thermometers are one of the most widely used medical devices for the measurement of body temperature during primary medical examination. Their vast utilization at home as well as in professional settings has resulted in the development of many different kinds of thermometers. However, no matter how well-built a device is, the importance of frequent calibrations cannot be denied as they ensure thermometer accuracy as well as reliability.
But what does it mean to calibrate a thermometer and how is it done? In the following article, let us not only understand what calibration is but also learn its impact on thermometer accuracy, reliability, as well as performance.
The Food and Drug Administration (FDA) advises in favor of a routine calibration of thermometers according to national as well as international standards.
What is Calibration?
As per the International Organization of Standardization, calibration is a method of making sure that the readings taken from a device are as close to the actual values as possible. During calibration, thermometer accuracy is analyzed. For this purpose, temperature readings of a stable heat source are measured with the device to be calibrated.
The obtained results are then compared with the actual readings measured with a standard/reference thermometer. If the difference between both the values is minor, then the thermometer being tested is considered accurate and thus calibrated.
Importance of Calibration
When extensively used, medical devices lose their accuracy little by little over time. Therefore, it is necessary to calibrate these instruments from time to time to make sure that they are giving accurate results. For this purpose, the device is frequently subjected to testing. Calibration is important because it ensures that the performance of the thermometer is up to the mark.
Impact of Calibration of Thermometer Accuracy
A calibrated thermometer gives the following advantages:
· High Accuracy
A thermometer that is subjected to calibration on a frequent basis is considered highly accurate and fit for measuring body temperatures as compared to devices that are not calibrated very often. In some settings, calibrating a thermometer on a daily basis is considered a standard practice. However, twice-a-year calibration is considered enough for a medical thermometer.
· Increased Effectiveness
When a thermometer is calibrated regularly, the device becomes more effective in performance. Therefore, thermometer accuracy in detecting fever and other temperature fluctuations is ensured.
· Longer Device Lifespan
Frequently calibrated systems are generally maintained well and have longer lifespans. This is due to the fact that during calibration, instrumental errors are noticed early on. Therefore, timely management of the problems leads to a well-maintained device that lasts for longer thus maintaining thermometer accuracy.
· High Patient Safety
If a thermometer is not capable of detecting temperature fluctuations correctly, small temperature changes often go unnoticed. Hence, the patient does not get proper treatment which jeopardizes the patient’s safety.
Therefore, patient safety is linked with thermometer accuracy as the chances of errors in temperature measurement are minimized with the use of well-calibrated systems.
· Decreased Cost of Treatment
Properly calibrated thermometers give accurate temperature readings in first employment. As a result, a suitable treatment regimen is set for the patient which effectively treats fever in a shorter time. Hence, the overall cost of therapy is lowered.
Ensuring Thermometer Accuracy: How are these Calibrated?
Thermometers measure temperature to indicate if we have a fever. But they can only do so with reliability only if the thermometer accuracy is intact. To ensure their performance, different types of thermometers are calibrated in the following ways:
· Oral Thermometers
For the calibration of oral as well as mercury glass thermometers, the device and a reference thermometer are immersed in a stable temperature-controlled water bath. After a while, both are taken out, readings are analyzed, and compared.
· Infrared Thermometers
Tympanic thermometers work on the principle of infrared technology which estimates body temperature based on the thermal energy given out by the movement of molecules in our blood. This thermal energy is often termed blackbody radiation.
Similarly, temporal artery thermometers measure these radiations from the temporal artery in the forehead following the same working principle.
For the calibration of these infrared devices, the to-be-tested thermometer and a reference thermometer are pointed toward a blackbody source which generates a calculated amount of thermal radiation.
After a specified time, both the thermometers are taken out and compared for their temperature measurements. If the difference between the values is not significant, the thermometer accuracy of the testing device is confirmed.
· Digital Thermometers
For the calibration of digital thermometers, the device is connected to a digital thermometer calibrator with the help of a probe. Set a temperature on the digital thermometer calibrator and wait until the testing thermometer matches with the set reading.
If the testing thermometer gives the exact same reading, there is no error in thermometer accuracy. However, if the digital thermometer keeps fluctuating its temperature readings, it is not fully accurate.
To ensure thermometer accuracy, it is recommended to calibrate the device every 6 months.
Maximum Possible Error (MPE)
Maximum permissible error or MPE is the extent of how much error in the measurement capacity of a device is acceptable. Generally, in the case of medical devices, a 0.5% error is considered unproblematic. Thus, if a temperature measuring device fluctuates up to 0.5°C from the standard reading, thermometer accuracy is not compromised.
A thermometer which indicates a temperature value within ±2°F or ±0.5°C of the actual reading is considered accurate.
Conclusion
Different kinds of thermometers are designed to take oral and rectal temperatures. In addition, many infrared thermometers are also available which are considered suitable for taking a child’s temperature.
However, in addition to proper usage methods as well as the right storage technique, a thermometer also needs to be calibrated often. Calibration ensures the thermometer accuracy and the reliability of the readings. Moreover, the overall lifespan of the device is also increased.
Hence, calibrating a medical device according to the recommended guidelines provides immense benefits. For buying reliable medical thermometers, vendors like Health Supply 770 should be approached as they not only ensure the provision of quality products but also offer satisfactory services.
PhD Scholar (Pharmaceutics), MPhil (Pharmaceutics), Pharm D, B. Sc.
Uzma Zafar is a dedicated and highly motivated pharmaceutical professional currently pursuing her PhD in Pharmaceutics at the Punjab University College of Pharmacy, University of the Punjab. With a comprehensive academic and research background, Uzma has consistently excelled in her studies, securing first division throughout her educational journey.
Uzma’s passion for the pharmaceutical field is evident from her active engagement during her Doctor of Pharmacy (Pharm.D) program, where she not only mastered industrial techniques and clinical case studies but also delved into marketing strategies and management skills.
