Variability of alpha-tocopherol values associated with procurement, storage, and freezing of equine serum and plasma samples.

TitleVariability of alpha-tocopherol values associated with procurement, storage, and freezing of equine serum and plasma samples.
Publication TypeJournal Article
Year of Publication1992
AuthorsCraig AM, Blythe LL, Rowe KE, Lassen ED, Barrington R, Walker KC
JournalAmerican journal of veterinary research
Volume53
Issue12
Pagination2228-34
Date Published1992 Dec
ISSN0002-9645
KeywordsAnalysis of Variance, Animals, Blood Preservation, Freezing, Horses, Plasma, Reproducibility of Results, Tissue and Organ Procurement, Vitamin E
Abstract

Recent evidence concerning the pathogenesis of equine degenerative myeloencephalopathy indicated that low blood alpha-tocopherol values are a factor in the disease process. Variables that could be introduced by a veterinarian procuring, transporting, or storing samples were evaluated for effects on alpha-tocopherol concentration in equine blood. These variables included temperature; light; exposure to the rubber stopper of the evacuated blood collection tube; hemolysis; duration of freezing time, with and without nitrogen blanketing; and repeated freeze/thaw cycles. It was found that hemolysis caused the greatest change in high-performance liquid chromatography-measured serum alpha-tocopherol values, with mean decrease of 33% (P < 0.001). Lesser, but significant (P < 0.01) changes in serum alpha-tocopherol values were an approximate 10% decrease when refrigerated blood was left in contact with the red rubber stopper of the blood collection tube for 72 hours and an approximate 5% increase when blood was stored at 20 to 25 C (room temperature) for 72 hours. Repeated freeze/thaw cycles resulted in a significant (P < 0.05) 3% decrease in alpha-tocopherol values in heparinized plasma by the third thawing cycle. Freezer storage for a 3-month period without nitrogen blanketing resulted in slight (2%) decrease in mean serum alpha-tocopherol values, whereas values in serum stored for an identical period under nitrogen blanketing did not change. A significant (P < 0.001) mean decrease (10.3%) in alpha-tocopherol values was associated with freezer (-16 C) storage of nitrogen blanketed serum for 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Alternate JournalAm. J. Vet. Res.