Real-Time Temperature Mapping in Ultra-Low Freezers as a Standard Quality Assessment

Adequate preservation of biospecimens has been proven to be critical to obtain reliable and reproducible results in genomics, transcriptomics, proteomics, and many other assays. Most biological assays can be performed on specimens preserved in -80 degrees C ultra-low freezers, but their quality can be influenced by temperature variability within storage units. Thus, regulatory standards such as those from the College of American Pathologists (CAP), the federal Clinical Laboratory Improvement Amendments, and standards from the Food and Drug Administration require temperature mapping, a standard quality assessment for accreditation when using ultra-low freezers for long-term biospecimen storage. The current mapping methods, providing annual/periodic data, may not be adequate indicators of temperature stability within the different zones of the freezers. In addition, they frequently require manual handling of biospecimens periodically, as they require freezers to be emptied or rearranged temporarily for the installation of temperature probes, risking the integrity of biospecimen quality. In this article, we describe a novel monitoring methodology based on real-time temperature reading of multiple zones by permanently installing thermocouples. An online cloud-based application records temperature variations within 1 minute intervals, and its 24/7 alert system triggers text alarm messages to a predefined set of users when temperature values increase above preset defaults. This provides an opportunity to take remedial action and to obtain a better-quality assessment. Our results indicate that real-time temperature monitoring at multiple zones of a freezer with a 1 minute resolution is a stable and sustainable methodology and, most importantly, lowers the risk of compromising the quality of the biospecimen. The design and use of the real-time monitoring system for ultra-low freezers is one of the acceptable methods by CAP to ensure the stability of biospecimen quality during long-term storage.