Ascorbic and dehydroascorbic acid measurement in human serum and plasma.
Author(s): Margolis SA, Ziegler RG, Helzlsouer KJ
Publication: Am J Clin Nutr, 1991, Vol. 54, Page 1315S-1318S
PubMed ID: 1962589 PubMed Review Paper? Yes
Suggested by: ISBER
Purpose of Paper
The purpose of this paper was to review the effects of specimen preservation and storage on blood ascorbic acid (AA) and dehydroascorbic acid (DHAA) levels.
Conclusion of Paper
AA was stable at -70 degrees C when preserved with dithiothreitol (DTT) in lyophilized plasma for 66 weeks and in frozen plasma for more than 57 weeks. Further, no change in AA was observed in DTT preserved whole blood after 24 h at 4 degrees C. Metaphosphoric acid (MPA) preserved plasma was stable for at least 13 weeks at -70 degrees C, but loss of AA and DHAA was evident by 24 h when stored at 4 degrees C. The loss of AA and DHAA in MPA-plasma was even more evident when specimens were stored at 25 or 50 degrees C.
Studies
-
Study Purpose
The purpose of this study was to evaluate the effects of preservative, storage temperature and condition on plasma AA levels. Some plasma specimens were spiked with AA for the study.
Summary of Findings:
AA was stable when preserved with DTT in lyophilized plasma for 66 weeks and in frozen plasma for more than 57 weeks. MPA-preserved plasma was stable for at least 13 weeks at -70 degrees C, but loss of AA and DHAA were evident after 24 h when stored at 4 degrees C. The loss of AA and DHAA in MPA-plasma was even more evident when specimens were stored at 25 or 50 degrees C leading the authors to recommend thawing of plasma at temperatures below 20 degrees C.
Biospecimens
Preservative Types
- Frozen
- Other Preservative
Diagnoses:
- Normal
Platform:
Analyte Technology Platform Small molecule HPLC Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Storage duration 13 weeks
57 weeks
66 weeks
80 weeks
Storage Storage temperature -70 degrees C
4 degrees C
25 degrees C
50 degrees C
Biospecimen Preservation Type of fixation/preservation Dithiothreitol
Frozen
Lyophilized
Metaphosphoric Acid
-
Study Purpose
The purpose of this study was to evaluate the effects of storage of DTT-preserved blood at 4 degrees C on plasma AA and DHAA. Following storage, blood specimens were centrifuged and the resulting plasma was preserved with MPA and stored at -70 degrees C until analysis.
Summary of Findings:
Storage of DTT-preserved whole blood for up to 24 hours had no effect on plasma AA levels. DHAA levels, which were 6.8-12% of AA levels, did not change in a consistent manner over the first 6 h. The authors note that in plasma, DTT completely converts DHAA to AA.
Biospecimens
Preservative Types
- Frozen
- Other Preservative
Diagnoses:
- Normal
Platform:
Analyte Technology Platform Small molecule HPLC Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Preservation Type of fixation/preservation Dithiothreitol
Frozen
Metaphosphoric Acid
Storage Storage duration 0 h
3 h
6 h
24 h
Biospecimen Aliquots and Components Centrifugation Centrifugation delays investigated