Buyer's guide
How to choose a temperature monitoring system you can defend at inspection
Choose on the evidence a supplier can hand your inspector, not on the dashboard. Six questions cover it: validation, calibration, alarms, service levels, your data and what happens to the system you have now.
3.8°C
The options
Three ways to keep temperature records
Each can be compliant for the right site. The difference is what happens at night, at the weekend and on the day of the inspection.
| Manual logs | USB or standalone data loggers | Wireless monitoring | |
|---|---|---|---|
| How readings are taken | A person reads a thermometer, usually once a day | The logger records at a set interval and stores it | Sensors send readings to a platform as they're taken |
| Out of hours | Nothing is seen until the next check | Recorded, but seen only when someone downloads it | Recorded, and an alarm goes to a named person |
| Finding out about an excursion | At the next check, from the min and max | When the logger is downloaded | When it happens, with the alarm and who responded |
| Records for the inspector | Paper sheets or a spreadsheet | Files on a PC, one logger at a time | One record across units and sites, with an audit trail |
| Calibration | Each thermometer, with its certificate | Each logger, with its certificate | Each sensor, with its certificate |
| Where it usually fits | A single fridge with a daily check | Transport, studies and spot checks | Sites that must know about a failure before morning |
General properties of each approach, not a comparison of products. Your rule (GDP, the Green Book, ISO 15189, BRCGS or the CQC) decides what you must evidence; the approach decides how hard that is.
What to ask
Six questions for any supplier
1. What validation evidence do we get, and who signs what?
A computerised system that keeps GxP records falls under Annex 11, and you stay accountable for your use of it. Ask what the supplier verifies and documents (the platform, each release), what they qualify on site (the hardware IQ and OQ) and what is left to you (your URS, configuration, DQ and PQ). Ask for the quality and technical agreement (QTA) that sets this out, and how a new release reaches you under your change control. See validation and Annex 11.
2. Who calibrates the sensors, and is it on their UKAS scope?
Ask for the schedule of accreditation, not just the word "UKAS". Check that the lab's scope covers the parameter (temperature, humidity, CO₂) and the range you use, in the lab or on site. If another lab does some of it, the certificate should name that lab. Ask how due dates are tracked. See calibration.
3. How does an alarm reach a person, and where is the record of what they did?
An alarm that only shows on a screen helps nobody at 3am. Ask how alerts are sent, how escalation works when the first person doesn't respond, and whether the system records who acknowledged the alarm, what they did and the corrective and preventive action (CAPA) that followed. That record is what your inspector or Responsible Person reviews.
4. What are the service levels, and when does the clock start?
Ask for the response and on-site attendance times in writing, by priority, and when each clock starts: from your call, from the supplier confirming the fault, or from agreeing that a visit is needed. Ask what happens out of hours and at bank holidays, and how a replacement sensor reaches you. See service agreements.
5. Who owns the data, and can we take it with us?
Your records belong to you. Ask how long data is kept, in what format you can export readings, alarms and the audit trail, and what happens to your records if you leave. Retention should meet your rule; GDP, for example, asks for backups of computerised data to be kept for at least five years.
6. What happens to the system we already have?
Few sites start from nothing. Ask whether the supplier can support your current sensors while you move, whether you can change site by site, and how your historical records stay available during the overlap. Ask what replaces a sensor that fails before you've moved.
Read next
The detail behind each question
Validation (IQ OQ PQ, DQ)
Who qualifies the hardware, who verifies the platform, and what stays with you.
Read moreAnnex 11
What the rule on computerised systems asks of a monitoring system.
Read the explainerCalibration
Calibration for every sensor we supply: traceable to national standards as standard, or UKAS accredited where you need it (temperature in our own UKAS accredited calibration laboratory No. 10723; other parameters through accredited partners).
Read moreService agreements
Response times by priority, and when each clock starts, in plain words.
Read more
20-minute compliance check
Want these questions answered for your site?
In 20 minutes we look at how you prove temperature to your inspector or auditor, and where the gaps are. You get a short list of what to fix first. No product tour.