Temperature variations in upright mechanical freezers.
We examined temperature deviations from the set temperature in specific locations, between-freezer temperature variability, and the effect of defrosting on temperature deviation in a group of 15 upright mechanical freezers, part of a biological sample bank of a large prospective cohort study. By using an Omega Type T Thermocouple Microcomputer thermometer with the freezers set at -80 degrees C, the internal temperature (12 locations in each freezer) ranged from -90 degrees C to -43.5 degrees C. Overall, internal temperatures tended to be appreciably warmer in the upper and front sections of the freezers. Upright front-loading mechanical freezers, which are widely used in research laboratories throughout the world, may not be optimally suited to preserve human biological samples for long-term banking in epidemiology.
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Department of Environmental Medicine, New York University School of Medicine, New York 10010, USA.
Garbers
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Rieper
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Toniolo
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D015331:Cohort Studies; D015925:Cryopreservation / Q000295:instrumentation*; D004813:Epidemiology; D005615:Freezing; D006801:Humans; D007753:Laboratories; D008838:Microcomputers; D011446:Prospective Studies; D012034:Refrigeration / Q000295:instrumentation*; D012106:Research; D013048:Specimen Handling / Q000295:instrumentation; D013821:Thermometers; D014015:Tissue Banks