Prime Scientific - Calibrating Your Cold Chain. A Recurring Dilemna.

The Dilemna

Spoiled vaccines can cost medical practices thousands of pounds, so it’s important to ensure your fridges are correctly calibrated to avoid any costly mistakes. Due to the crucial nature of the materials held inside the cold chain, temperature control monitoring in medical refrigerators is critical. Vaccines, blood products, and other drugs must be stored in cold storage at certain temperatures to preserve efficacy and safety.

Failure to follow these temperature limits can result in product deterioration, rendering it useless or possibly dangerous to patients. Staff training is necessary to guarantee that suitable practices are followed to keep acceptable temperature ranges.

Laboratory refrigerators have advanced temperature control systems, typically incorporating digital thermostats or temperature controllers. These systems enable users to set and maintain specific temperature ranges suitable for the preservation and integrity of the stored items.

When the temperature inside a laboratory refrigerator deviates from the desired range, the thermostat or temperature controller detects the change and activates the cooling mechanism. This prompts the compressor to engage, initiating the circulation of a refrigerant through coils within the refrigerator. As the refrigerant absorbs heat from the interior, the temperature decreases, bringing it back within the designated range.

Laboratory refrigerators often feature additional temperature monitoring and alarm systems to ensure the utmost precision and provide an alert if the temperature goes beyond acceptable limits. These safeguards are crucial for preserving delicate specimens and maintaining the quality and reliability of scientific experiments and research materials.

The Solution?

In order to perform the calibration for your fridges and freezers in the lab, you need the following tools:

• NIST-traceable digital thermometers
• Refrigerators
• Freezers

The steps to follow are as follows.

1. Ensure that the Refrigerator and shelves are clean. If not then clean with a non- shedding lint free duster or cloth dipped in disinfectant solution (wherever applicable). 
2. The distance between air outlet and side wall should be at least 200 mm.
3. Take a beaker of 100 ml capacity.
4. Fill the beaker with 80 ml of silicone oil.
5. Place the beaker containing silicon oil on the lower shelf of the refrigerator.
6. Dip the calibrated and certified thermometer in the beaker containing silicon oil.
7. Close the door of the refrigerator, and wait for 15 minutes to stabilize the temperature inside the refrigerator
8. Observe the temperature of a calibrated thermometer
9. Repeat the above steps for all the shelves of the refrigerator/freezer.
10. Compare the result with acceptance criteria and take valid calibration authorization
11. Report any discrepancy observed during calibration of instrument to Section In-charge or his representative for corrective and preventive action
12. Record the observations
13. Always Take the reading when an instrument has attained constant temperature in the chamber.
14. Do not forget to Check the Calibration of the Thermometer.
15. Handle the instrument carefully.

References

1. https://www.coolmed.co.uk/knowledge/medical-fridges-and-calibration-getting-it-right/
2. https://arctiko.com/us/the-vital-role-of-temperature-monitoring-in-medical-refrigeration/
3. https://www.360medical.ca/blogs/news/temperature-control-laboratory-fridges-importance-best-practices
4. https://forensicresources.org/wp-content/uploads/2019/07/Procedure-for-Equipment-Calibration-and-Maintenance-01-25-2019.pdfhttps://www.pharmaguideline.net/sop-for-operation-and-calibration-of-refrigerator/