Effects of Repeated Freeze-Thaw Cycles on Concentrations of Cholesterol, Micronutrients, and Hormones in Human Plasma and Serum

In a study, three cycles of freezing and thawing had almost no effect on concentrations of cholesterol, micro-nutrients, and most of the hormones investigated (data not shown). For estrone, estradiol, testosterone, and SHBG, there was appreciable variation within the first three cycles, but the degree of variability was considerably less than the respective CVs. Although there were greater losses after 6 or 10 cycles for a few other analytes, these were too small to have a meaningful effect on results.