Cold Chain Failure Case Studies
Here are two real life cold chain cases that occurred recently that I would like to bring to your attention to emphasis why we do not recommend using a fridges in-built min/max display to record from.
Case 1
Large hospital ED carrying a large inventory of vaccines. Using a pharmaceutical grade refrigerator. Staff carried out daily recording of minimum and maximum from the fridges built in display.
Display showed no deviation from the 2C -8C threshold for the month. Staff then downloaded datalogger after 30 days and found that the temperatures were outside the threshold for approximately 50% of the month even though the fridge displayed a “normal” storage temperatures during that period.
Logger was send away for calibration and was reported to be accurate with the manufacturers specification. The fridge controller needed adjustment. Result meant immunised patients had to be recalled. Cost high.
Case 2
Small GP with under bench pharmaceutical grade fridge reported a fault with their logger. Data on the logger showed that the fridge had gone through a sustained cold cycle lower than 2C for a large part of the day. However the nurse reported that the readings from the fridge where within normal 2-8C threshold. So It was “assumed” that the logger was reading incorrectly. Logger was checked and found to be accurate. Fridge service showed no fault and at the time of service was operating normally.
The present MOH vaccine guidelines advise that minimum maximum temperatures need to be recorded daily. We recommend the fridge in-built display should-not be used and instead use an independent calibrated thermometer or datalogger with min/max display, to undertake this requirement.
It is best to leave the fridge to do its job of maintaining and controlling a cold environment within 2-8C and only use an independent device to record all temperature information, whether it be daily min/max values or historical temperature data.