How and how long to store urine samples before albumin radioimmunoassay: a practical response.

Author(s): Giampietro O, Penno G, Clerico A, Cruschelli L, Cecere M

Publication: Clin Chem, 1993, Vol. 39, Page 533-6

PubMed ID: 8448872 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 temperature, duration, and container on the stability of urinary albumin. 21 pooled urine specimens were used to determine the stability of albumin at -20 degrees C over a period of 4-21 months. All other storage conditions and durations were investigated using individual urine specimens which were also assayed prior to storage.

   Summary of Findings:

   No differences in albumin concentration were observed between specimens stored in glass, polystyrene, or polypropylene tubes at -20 degrees C over the course of 2 months. Storage of urine at room temperature for 24 h, 4 degrees C for 24 or 72 h, or -20 degrees C for up to 2 months did not significantly affect albumin concentration compared to measurements taken on urine within 1 hour of collection. Significant decreases in urinary albumin concentration were observed when urine was stored at -20 degrees C for 2 y (-13.2%) or 4-5 y (-21.8%) compared to concentrations measured prior to the long-term storage. When pooled urine was repeatedly assayed during storage at -20 degrees C, 3 of 21 pools showed significant decreases in albumin concentration over the course of 4-21 months.

   Biospecimens

   • Bodily Fluid - Urine

   Preservative Types

   • None (Fresh)
   • Other Preservative
   • Frozen

   Diagnoses:

   • Normal
   • Diabetes Type 1
   • Diabetes Type 2

   Platform:

   Analyte	Technology Platform
   Protein	Radioimmunoassay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Type of storage container	Glass Polystyrene Polypropylene
   Storage	Storage temperature	18-20 degrees C 4 degrees C -20 degrees C
   Preaquisition	Biomarker level	Normo-albuminuric Microalbuminuric Macroalbuminuric
   Storage	Storage duration	1 h 24 h 24 h 72 h 7 d 14 d 21 d 28 d 60 d 4-21 months 2 y 4-5 y
   Biospecimen Preservation	Type of fixation/preservation	Frozen None (fresh) Refrigeration

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