[The use of microwave ovens to thaw frozen rat serum]

This study was performed to examine the optimum conditions for thawing frozen rat serum in a microwave oven (Toshiba, Type ER-1345 JF). The thawing temperature must be kept at 37 degrees C or less to maintain the blood biochemical values within the normal ranges because the values of alkaline phosphatase, cholinesterase, glucose and albumin were markedly altered at 40 degrees C or above. For thawing frozen serum, the best conditions were as follows: a sample volume of 0.5 ml was convenient to control the thawing temperature; locating the samples 10-12 cm out from the center of the turning table in the oven resulted in a thawing temperature of 10-20 degrees C; a microwave irradiation time of 1 min 45 sec thawed samples frozen at -20 degrees C. Using the sample plate that we made, 80 samples could be thawed at the same time under almost the same conditions. The blood biochemical values obtained from sera thawed in the microwave oven showed good correlation with those from sera in a water bath (37 degrees C) and had excellent reproducibility. These results suggest that thawing frozen rat serum by microwave irradiation is rapid and easy and without adverse effects on the blood biochemical values.