Who is required to use a data logger?

All new VFC providers, practices that are open 2 days a week or less, and practices needing to replace their primary or back-up thermometer are required to purchase and use data loggers to monitor temperatures. Note: beginning in 2017, all VFC providers will be required to use data loggers to monitor the temperatures in their storage units. “

What is a data logger?

A data logger is an electronic device that reads and records temperatures and stores them in its internal memory. This kind of device is also known as “continuous temperature monitoring” device. The temperatures recorded by a data logger can be viewed on a computer and saved as an electronic or paper file.

Why is it important to use a data logger in clinic?

• Recording temperatures 24/7, at pre-set time intervals, gives clinic staff details of how long vaccines are stored at those temperatures.
• Having accurate, detailed information on any out-of-range temperatures (i.e., dates, temperatures, length of time temperatures were out of range), helps clinic staff decide what actions to take when a logger’s temperature alarms trigger.
• Having temperature information from a data logger lets clinic staff know how well or not a refrigerator or freezer used to store vaccines is working while its temperatures are recorded by the logger.

What should one look for when buying a data logger?

Before you buy, call the vendor or manufacturer to make sure:

• The data logger meets CA VFC requirements for use in a vaccine storage unit.
• The data logger can be used in a vaccine-storing refrigerator, freezer, or both.
• The data logger you order will come with a certificate of calibration for a calibration cycle of at least one and no more than two years.
• The data logger has features and functions that are useful to your clinic staff. For example, the size of the device display or length of the AC adaptor and/or sensor cord attached to the device’s probe may have to be a particular size and length suitable for staff and clinic vaccine storage units.

The CA VFC Program does not endorse or promote specific temperature monitoring devices. VFC Program staff can, however, offer guidance by referencing the CA VFC Program’s technical specification requirements.

No company, person, or retailer may use the term “VFC Representative” without any official affiliation to the California Department of Public Health Immunization Branch.

What type of temperature probe should be used with a data logger?

The temperature probe senses the temperatures in the vaccine storage unit. Temperature probes should be buffered so that temperature monitoring devices measure the temperature of vaccine vials – not the temperature of the air in a storage unit.

• A buffered probe is a temperature probe immersed or inserted in one of the following:
  • A vial filled with liquid (e.g., glycol, ethanol, glycerin)
  • A vial filled with loose media (e.g., sand, glass beads)
  • A solid block of material (e.g., Teflon®, aluminum)
• When a temperature probe is obtained separately from a vial with fluid buffer material, it should be in a vial filled with 15 mL to 60 mL of fluid to provide sufficient thermal buffering.
• A vial containing less than 15 mL of fluid buffer material can be suitable as long as the probe and buffer vial are sold as a system designed to achieve proper immersion. The smaller volume of buffering media will work to monitor temperature.
• Probes that are permanently imbedded in buffer are acceptable as long as the temperature monitoring system for the entire unit may be calibration-tested.

What are the temperature alarm settings one should use with a data logger for refrigerator or freezer units storing VFC-supplied vaccine?

How do data loggers show that an alarm was triggered because of an out-of-range temperature?

Data loggers come with visual alarm indicators on the LCD screens and, depending on the model, audio alarms too. More advanced features include automatic, remote capability so a phone call, text message, or email can be sent to a smart phone when excursions occur.

When an alarm activates, clinic staff must know how to respond and take immediate corrective action following clinic and VFC Program response procedures.

Does using a data logger eliminate having to manually document temperatures twice daily on VFC temperature paper logs?

No. Temperatures must be read and manually recorded twice each day: once in the morning, and again before the work day ends, even when a continuously recording/graphing data logger is being used as a primary thermometer.

Although a continuous temperature monitoring device may automatically reset itself at midnight, twice-daily manual recordings help ensure that clinic staff sees temperature (current, MIN, and MAX) readings and notice any visual alarms triggered by out-of-range temperatures.

Our old thermometers are due for recalibration soon. Should we buy data loggers instead of having the thermometers recalibrated?

Yes, absolutely! Here are two important things to consider:

• Temperature monitoring devices must meet VFC Program requirements. A new data logger may be more likely to meet CA VFC requirements than your old thermometers.
• The VFC Program is transitioning from thermometers to digital data loggers. Why not get a head start?

Do data loggers need to be calibrated?

VFC requires all thermometers used in storage units with VFC-supplied vaccine be calibrated. A DDL is a thermometer that must be calibrated before it is used in a vaccine storage unit. Check that any data logger you buy includes a certificate of calibration that meets VFC requirements. Clinic staff is responsible for keeping certificates of calibration up to date.

What is the cost of calibration for data loggers?

The cost of calibrating a basic data logger should be about the same as calibrating a regular thermometer. The cost of calibrating a more advanced continuous temperature monitoring system will vary depending on its enhanced functions and number of probes.

See also:

• Frequently Asked Questions about Thermometer Calibration
• Data Logger Calibration FAQs
• How to Get Thermometers Calibrated

What type of temperature monitoring device or system should a clinic buy?

There are single stand-alone data loggers that can be used with each vaccine storage unit and a single PC. There are larger computer-networked systems used with multiple temperature sensors at various clinic sites. Data loggers can also be part of temperature alert system that notifies clinic staff through email, text, or phone calls when temperatures are out of range.

The best continuous temperature monitoring devices, whether stand-alone or more complex, a clinic buys may depend on:

• what is required for compliance with the VFC Program
• how well clinic staff responsible for temperature monitoring are trained to use it
• time available for clinic staff to download and analyze temperature data
• the budget available to invest in a temperature monitoring device or system
• the size of the clinic practice
• clinic routine temperature monitoring procedures

The lowest priced data logger may not meet VFC requirements. More sophisticated, higher cost temperature monitoring systems that include data loggers, remote alert capabilities, and enhanced features may also not be best for your clinic if the system is not user-friendly or temperature probes are not in a buffered medium.  Begin by making sure what you buy meets both VFC requirements and your practice’s needs.

Who sells temperature data loggers?

Many companies sell data loggers, but specialized medical equipment suppliers and manufacturers’ distributors will know most about these devices and have the best information about them.

Plan on comparing different product models, features, costs, and asking questions to get the device and/or temperature monitoring and alert system that best meets your clinic’s needs.

Here are some product vendors/and or distributors. This list is not exhaustive and includes only common search results.