Repeated freezing and thawing of peripheral blood and DNA in suspension: effects on DNA yield and integrity.

Author(s): Ross KS, Haites NE, Kelly KF

Publication: J Med Genet, 1990, Vol. 27, Page 569-70

PubMed ID: 2231649 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 of EDTA blood or extracted DNA on DNA yield and fingerprinting pattern. K+ EDTA blood was obtained from 5 healthy patients, and one aliquot was used for immediate DNA extraction while 5 additional aliquots were frozen immediately in a dry ice/ethanol bath. The frozen blood was subjected to 1, 5, 10, 20 or 40 freeze-thaw cycles with thawing at 37 degrees C. DNA extracted from fresh specimens was stored at 4 or -70 degrees C or subjected to 5, 10, 20 or 40 freeze-thaw cycles.

   Summary of Findings:

   Compared to yields from fresh specimens, frozen specimens yielded 25% less DNA. Increasing the number of freeze-thaw cycles did not lead to further decreases in DNA yield. Freeze-thaw cycling of blood had no effect on the DNA fingerprinting band pattern. The authors also report that freeze-thaw cycling of extracted DNA samples had no effect on DNA fingerprinting band pattern.

   Biospecimens

   • Bodily Fluid - Blood

   Preservative Types

   • Frozen
   • None (Fresh)

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   DNA	Fluorometry
   DNA	Electrophoresis

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Freeze/thaw cycling	0 cycles 1 cycle 5 cycles 10 cycles 20 cycles 40 cycles
   Biospecimen Preservation	Type of fixation/preservation	Frozen None (fresh)

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