Long-term (in)stability of folate and vitamin B12 in human serum.

Author(s): Jansen EH, Beekhof PK, Cremers JW, Schenk E

Publication: Clin Chem Lab Med, 2012, Vol. 50, Page 1761-3

PubMed ID: 23089705 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 storage on folate and vitamin B12 levels in serum from blood donors. Before measurement all specimens were stored on ice for <1 h.

   Summary of Findings:

   Compared to levels measured within 4 hours of blood collection, folate levels were 17% lower after storage of serum for 4 days at 4 degrees C and 14% lower after storage of serum for 14 days at -20 degrees C, but were unaffected by storage of serum for up to 12 months at -70 or -196 degrees C. Despite the declining folate concentration with progressive storage of serum at -20 degrees C, the values obtained after storage were very strongly correlated with original levels (r=0.97). In contrast to folate, serum vitamin B12 was stable for 4 days at 4 degrees C (the longest interval examined) and for at least 2 months at all other temperatures. After 6 months or 12 months of frozen storage, a small decline in serum vitamin B12 levels was observed, but a similar decline was also noted in the control specimens so the authors attribute the decline to a systemic error in the measurement.

   Biospecimens

   • Bodily Fluid - Serum

   Preservative Types

   • Frozen
   • Other Preservative

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Small molecule	Clinical chemistry/auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage temperature	4 degrees C -20 degrees C -70 degrees C -196 degrees C
   Storage	Storage duration	<4 h 4 days 14 days 1 month 2 months 6 months 12 months
   Biospecimen Preservation	Type of fixation/preservation	Frozen Refrigeration

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