Much has been made in our posts regarding the importance of storing valuable vaccines at correct temperatures in scientific refrigerators and freezers. The Centers for Disease Control and Prevention (CDC) provides explicit guidelines on specifying and using vaccine storage refrigeration equipment.
Using approved storage equipment is one part of the story. Storage units must be continuously monitored to insure temperatures are within specification. As noted by the CDC accurate temperature history that reflects actual vaccine temperatures is imperative to effective vaccine management. Therefore every freezer and refrigerator unit used to store vaccine should be equipped with calibrated thermometers with an NIST Certificate of Traceability and Calibration Testing (also known as Report of Calibration).
Automated temperature display, monitoring, alarming and recording devices are crucial components in vaccine storage. Temperature control systems range from dial-type thermostats to digital microprocessor temperature controllers and displays. In the real world, however, healthcare personnel, ideally under the supervision of a vaccine coordinator, bear the ultimate responsibility for avoiding vaccine spoilage due to improper storage temperatures and possible malfunction of temperature control mechanisms.
First on the list of CDC recommendations is visually reading and manually documenting vaccine storage temperature twice each work day along with the minimum and maximum temperatures each day. If temperature excursions beyond the set storage unit temperature are revealed immediate corrective action can take place. Such inspections also allow checking stock inventory and expiration dates.
Temperature Monitoring and Recording Devices
Second on the list is the use of a digital data logger to record and store temperatures on a continuous basis. These external devices are connected via sensor ports or wires passing behind the hinge-side door gasket to internal temperature probes encased in a glycol-filled vial. Such vials more accurately reflect vaccine temperature than air temperature in the refrigeration unit. An example is a USB temperature logger available from Tovatech that is installed using NIST traceable probes that measure and save in 15-minute intervals. Data can be read on any computer.
Another example is the iLab 600 Temperature Monitoring System also available from Tovatech. It acquires, remotely stores and instantly retrieves regulatory compliant data reporting on the performance of lab freezers and lab refrigerators. It collects data from an internal buffered probe attached to an external pod that in turn is connected to the facility’s LAN, and incorporates a sophisticated high/low temperature alarm along with other features to alert staff on or off site.
However temperature information is obtained, the CDC recommends reviewing it on a weekly basis. The healthcare facility should have in place appropriate responses to temperature excursions. Archive data for at least three years or according to state regulations.
Temperature Alarming Systems
The provision of hi/low temperature alarming systems is a key element of CDC vaccine storage guidelines. Depending on the refrigerators or freezers used, alarming systems can be built in or installed as auxiliary equipment and can be equipped with remote alarm contacts to alert personnel in other areas of the building. More sophisticated units such as the iLab 600 mentioned above are able to alert designated off-site personnel via email, text, phone or pager.
Vaccine Storage Thermometer Checklist
The CDC Vaccine Storage and Handling Toolkit available online is an excellent resource for all aspects of this vital topic. Here’s a checklist of do’s and don’ts regarding vaccine storage thermometers:
- Provide continuous monitoring information with an active display
- Be a digital thermometer with a probe in a glycol-filled bottle
- Include an alarm for out- of- range temperatures
- Have a reset button if using a data logger with a min/max display
- Be capable of showing current temperature as well as minimum and maximum temperatures
- Be within +/-.5°C accuracy (+/-1°F)
- Have a low battery indicator
- Fluid-filled biosafe liquid thermometers
- Bi-metal stem thermometers
- Food thermometers
- Household mercury thermometers
- Chart recorders
- Infrared thermometers
- Thermometers that are not calibrated
Contact the scientists at Tovatech for further details on these important considerations, and for help on selecting vaccine refrigeration systems that meet your storage requirements.