Repeated freezing and thawing does not generally alter assay results for several commonly studied reproductive hormones

Rosario Reyna, Kyle D. Traynor, Gene Hines, Larry R. Boots, Ricardo Azziz

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Objective: To determine the effect of repeated freezing and thawing, and storage temperature, on the assay results of commonly measured reproductive hormones, and sex hormone-binding globulin (SHBG) in human serum. Design: Prospective laboratory study. Setting: Academic medical center. Patient(s): Four men and three pregnant women in the third trimester. Intervention(s): Pooled serum from men and pregnant females were frozen at either -20°C or -70°C. Aliquots were then subjected to repeat freeze/thaw cycles, from 1 to 10 times, and assays were performed after the final freeze/thaw cycle. Main Outcome Measure(s): Assay results for eight hormones (FSH, LH, PRL, androstenedione (A), 17α-hydroxyprogesterone, P, insulin, and SHBG, as a function of the number of freeze/thaw cycles and storage temperature. Result(s): Only SHBG in male serum at -20°C and P in pregnant serum at -70°C showed statistically significant decreases in assay results with repeated freeze/thaw cycles (3.3% and 1.1% per cycle, respectively). All other analytes did not show significant changes as a function of freeze/thaw cycles or storage temperature. Conclusion(s): There is no consistent or predictable alteration in the results of SHBG, or the glycoprotein and steroid hormones evaluated, as a function of repeated freeze/thaw or the storage temperature of human serum.

Original languageEnglish (US)
Pages (from-to)823-825
Number of pages3
JournalFertility and sterility
Issue number4
StatePublished - 2001


  • 17α-hydroxyprogesterone
  • Androstenedione
  • Cryostorage
  • FSH
  • Glucose
  • Hormones
  • Insulin
  • LH
  • Measurement
  • P
  • Prolactin

ASJC Scopus subject areas

  • Reproductive Medicine
  • Obstetrics and Gynecology


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