In 2012, the Harvard Brain Tissue Resource Center lost 150 of its stored frozen brain samples, including one-third of the world’s largest collection of autism brain tissue. At the time, associates of the Center said the loss of those brains could set autism research back by a decade. The culprit was an improperly monitored freezer with an ineffective alarm system.
It happened again in 2018, when two US fertility clinics each lost thousands of stored eggs and embryos due to freezer failures. And just last year, stem cells from 56 pediatric cancer patients were lost when a freezer malfunctioned at a US children’s hospital. These are just a few examples of samples having been compromised due to equipment failures, compounded by ineffective systems and a lack of monitoring. Indeed, laboratory freezer failures are a common occurrence—ask most scientists, and they have probably had a freezer fail on them at one time or another. But when it comes to precious patient samples, prevention of these losses is critical.
Freezers may fail for any number of reasons. There may be a facility-wide power outage. Compressors may break down. Temperatures may be slow to stabilize if the freezer door is frequently being opened. Regular freezer maintenance may not be performed. The list goes on.
But when failures occur, damage to, or loss of stored samples is not inevitable. When samples do get destroyed, as in the high-profile cases noted above, it’s often ultimately down to a failure of the systems and processes that are meant to react to deviations in a freezer’s temperature.
Although freezers contain internal temperature sensors, most labs opt to put independent monitoring systems in place as a backup in case the internal sensors fail.
However, even with such systems in place, issues can still arise. Independent monitoring systems certainly reduce reliance on the equipment itself to monitor temperature deviations, but in practice, there are several other important considerations.
One reason why so many monitoring systems are unreliable is that they rely on data logging rather than real-time data acquisition. The critical distinction between the two is that data loggers log temperature data in batches for future extraction, whereas real-time data acquisition systems measure data and compare it to pre-set parameters on a continuous basis. With data loggers, if a batch of data is lost or there is an urgent failure, lab personnel may be unaware of temperature deviations until samples have already been compromised. This creates a false sense of security.
Another reliability issue some laboratory freezers run into is low-quality temperature sensors. An obvious consequence of degraded sensors is that they may fail to recognize temperature deviations when they occur. Equally problematic is when sensors trigger false alarms even when no temperature deviation has occurred. If false alarms go off on a regular basis, laboratory personnel may eventually stop responding to them or turn their alarm systems off altogether—a phenomenon known as alarm fatigue.
Freezer failures are missed for a number of reasons. This graphs shows how quickly freezer temperatures spike after a compressor fails.
Freezer failures are common and often lead to sample loss, but there are measures that laboratories can take to prevent this. The solution is three-fold:
It is essential that clinical laboratories acquire monitoring systems that are independent of the equipment being monitored. Such systems should feature high-quality, industrial-grade sensors to avoid false alarms.
When a freezer reaches user-specified temperatures, the Hospitals and medical centers rely heavily on their cold storage systems to preserve precious patient samples. independent monitoring system should notify lab personnel by setting off an alarm and sending alerts via phone, text message or email.
Many monitoring systems log data in intervals of 15 minutes to an hour and upload it all in one batch. But when temperature deviations occur in freezers containing patient samples, they require immediate attention—working off of delayed data is insufficient. A real-time data acquisition system is much more robust than a data logger as it provides a constant stream of temperature data.
Although numerous factors are usually at play when a freezer fails, the human factor is arguably the weakest link. To avoid relying solely on the people in the lab to respond to monitoring systems, laboratories can invest in a laboratory monitoring service. An ideal service has live agents on call 24/7 to help manage alarms for customers, similar to a home alarm monitoring service. Laboratory monitoring service agents can also perform additional tasks like data analysis, including predictive analytics on equipment likely to fail, root cause analysis on deviations that occurred, and generation of quality reports for audits or external regulatory compliance.