FELIPE DE LOURA DA ROSA

Metrology Analyst

There are several care and restrictions that a blood bank needs to have to give reliability to its patients. After all, have you already stopped to think about how and where the samplers, blood bags of donors, plasma, and others blood products are stored?

These products are stored in refrigerated chambers, thermal chambers, freezers and ultra-freezers, devices especially manufactured to maintain temperature sensitive products. However, how to ensure that the device responsible for storage is working properly and that the device will not be damaged by temperature changes?

It is possible to certify the accuracy of the device by thermal qualification of performance and calibration of temperature meters.

The importance of doing qualifications and calibrations

Imagine that a refrigerated chamber that stores blood bags (which must to be stored at temperatures of 2 °C to 6 °C) is measuring with a 4 °C mistake, that the chamber does not return to its original range after a door opening, or that some part of the chamber may be cooling more or less than the determined temperature range. In any of these cases, the product will suffer irreversible damage. This is the importance of making thermal qualifications of performance and calibrations on all equipment that, in general, may interfere with the quality of the final product.

The calibration of temperature sensors are performed by direct comparison with a calibrated temperature standard, where all sensors are introduced in a thermal medium (thermostatic bath or dry block calibrator). The calibration is performed at the desired temperature points. This process creates a calibration certificate. This calibration certificate brings identification, manufactured, serial number (if it has a serial number), sensor type, among others requirements, besides the error and uncertainty that the equipment has presented during a calibration.

Thermal performance qualification in equipment that stores products such as blood, plasma, samples, etc. is performed as follows:

Twelve temperature sensors are installed inside the equipment. One sensor must be close of the sensor of the equipment and the other sensors must be distributed in order to cover all the volume, as we can see in figure below.

The equipment must be qualified with load, that is, it must contain products that are stored daily. Thermal qualification of performance is carried out over 24 hours, during which time the equipment must undergo door openings in order to verify the performance for temperature limits.

It is performed a deliberate shutdown of the energy for five minutes at the end of the qualification to verify if the temperature will exceed the predefined limits in this period.

After the process is finished, the temperature data will be downloaded to generate a certificate with the results. Besides the results, the certificate must bring equipment identification, manufacturer, serial number, model, dimension, graph of temperature readings, photos of the equipment, figure with the distribution of the sensors, conclusion, etc.

NOVUS Metrology Lab uses high-performance, accurate data loggers and Pt100 sensors to measure temperatures during the calibration-qualification process, delivering reliable results.

Periodic equipment calibrations and thermal qualification of performance are important to ensure perfect operation of equipment that stores sensitive products. A reliable company that always uses the same high accuracy equipment offers more reliability to the methods and, therefore, greater safety for health institutions and patients that use blood components and blood products.