Effect of repeated freezing and thawing on vitamins and hormones in serum.

Author(s): Hsing AW, Comstock GW, Polk BF

Publication: Clin Chem, 1989, Vol. 35, Page 2145

PubMed ID: 2791293 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of freeze-thaw cycling on vitamins and hormones in pooled serum from healthy individuals. 15 aliquots were available for vitamin assays but only 5 were used for steroid assays. Hormones were assayed by an outside laboratory, and vitamins were assayed in house, but all were measured by an unspecified method. Specimens were frozen at -73 degrees C, and thawing conditions were not specified.

   Summary of Findings:

   Levels of vitamins (retinol, retinol binding protein, carotenoids, beta-carotene, lycopene and tocopherol) changed by less than 3% between 2 and 4 freeze-thaw cycles, while levels of hormones (testosterone, dihydrotestosterone, prolactin, luteinizing hormone, and follicle stimulating hormone) changed by less than 9%. The authors state that a larger sample size would be necessary to determine the significance of changes in hormone levels.

   Biospecimens

   • Bodily Fluid - Serum

   Preservative Types

   • Frozen

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Glycoprotein	Clinical chemistry/auto analyzer
   Small molecule	Clinical chemistry/auto analyzer
   Steroid	Clinical chemistry/auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Freeze/thaw cycling	2 cycles 3 cycles 4 cycles

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