Digital Data Loggers
Continuous temperature monitoring is an essential component of the provider’s vaccine management plan. Providers participating in any of California’s vaccine programs agree to equip storage units housing publicly supplied vaccines with digital data loggers that meet program requirements. Providers must also have at least one backup, battery-operated device for use if the primary device breaks or does not meet calibration requirements, or for use during emergency vaccine transport. Depending on practice size, additional devices might be needed.
Benefits
Data loggers provide an accurate report of vaccine temperatures over time and report how long vaccines have been exposed to out-of-range temperatures that compromise vaccine stability. Data loggers
- Monitor vaccine temperatures continuously—even when the practice is closed,
- Notify clinic staff of temperature excursions during non-business hours,
- Prevent unnecessary vaccine losses when excursion time frames cannot be precisely determined, and
- Record temperature data as an electronic file for analysis of temperature trends over time.
Purchasing Considerations
Data loggers are certified for use in a refrigerator, freezer, or both. Devices might be simple, stand-alone devices (might be easier to use) or come with enhanced cloud-based technology, remote access to temperature readings, and sensors at multiple sites (require more training). Data loggers might also notify clinic staff of temperature excursions through email, text, or phone calls. Cheaper devices might not meet program requirements. The most suitable data logger might depend on provider budget, staff training needs, and clinic size and needs.
Specifications
Data loggers must meet program requirements. Click to explore these topics:
Device Specifications
| Feature | Description |
| Accuracy | +/-1°F (+/-0.5°C) |
| Logging interval | Programmable (maximum 30-minute interval) |
| Memory storage | 4,000 readings or more |
| Buffered probe | Only use buffered probe bundled with device Detachable from unit, or permanently embedded in buffered material if temperature monitoring system can be calibrated Immersed in vial filled with thermal buffer material, including liquid up to 60 mL (e.g., glycol, ethanol, or glycerin), loose media (e.g., sand or glass beads), or solid block of material (e.g., Teflon® or aluminum) |
| Digital display | Active external display Current, MIN & MAX temperatures Low-battery indicator |
| Alarm capabilities | Programmable Visual or audible alarm to signal out-of-range temperatures |
| Reporting | Must generate summary report of recorded temperature data since device was last reset; summary reports must include MIN and MAX temperatures, total time out of range, and alarm settings; devices that only generate CSV data files or Excel spreadsheets are not acceptable. |
Unacceptable Devices
- Thermometers (e.g., round dial thermometers, fluid-filled and/or min-max bar thermometers, household-use and kitchen thermometers, infrared temperature guns, alcohol or mercury thermometers, and bi-metal stem thermometers), which tend to reflect air temperature
- Chart recorders (i.e., units that plot temperatures on printed graphs)
- Data loggers that do not have probes immersed in a vial filled with liquid, loose media, or a solid block of material per program requirements
- Virtual or simulated technologies (e.g., devices with bullet probes, solid vial simulators, modified simulators, or virtual buffering technology)
Certificate of Calibration Requirements
Each data logger must have a valid Certificate of Calibration Testing (also known as Report of Calibration). New devices come with a certificate good for typically one to two years. Certificates must comply with specifications in the Certificate of Calibration Quick Guide (PDF), including laboratory name and address, device name and model number, serial number calibration date, and measurement results.
Ready to Buy?
CDPH does not endorse or promote specific devices. Potential vendors and distributors include Control Company, Control Solutions, DeltaTrak, Fisher Scientific, MicroDAQ, Nova-Tech International, and VWR.
Before purchasing, contact the vendor or manufacturer to ensure devices meet program requirements. Refer to Digital Data Logger Pre-Purchase Worksheet (PDF) and Device Feature Comparison Guide for more guidance.
Configuring Devices
Use Data Logger Setup & Use (PDF) to configure primary and backup data loggers. Refer to the device’s product guide or video to learn how to use it. Contact vendor or manufacturer for all questions regarding setup and functionality.