Microalbumin and freezing.

Author(s): Innanen VT, Groom BM, de Campos FM

Publication: Clin Chem, 1997, Vol. 43, Page 1093-4

PubMed ID: 9191573 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effect of freezing urine specimens for 1 or 3 weeks on MA quantification.

   Summary of Findings:

   MA levels were measured in 23 fresh urine specimens and again after freezing with post-thaw mixing for 1 and 3 weeks. MA concentrations in the urine frozen for 1 or 3 weeks were comparable to those observed in fresh urine.

   Biospecimens

   • Bodily Fluid - Urine

   Preservative Types

   • Frozen
   • None (Fresh)

   Diagnoses:

   • Other diagnoses

   Platform:

   Analyte	Technology Platform
   Protein	Clinical chemistry/auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Preservation	Type of fixation/preservation	Frozen None (fresh)
   Storage	Storage duration	1 week 3 weeks
   Storage	Storage temperature	-20 degrees C

   View more

2. Study Purpose

   The purpose of this study was to determine the effect of freezing and post-thaw mixing on MA quantification from 39 urine specimens.

   Summary of Findings:

   MA levels were measured in 39 fresh urine specimens and again after freezing for 1 week with and without mixing. In specimens that were frozen and not mixed prior to MA quantification, 77% had MA levels decrease by >30%. The mean decrease in MA levels among unmixed frozen specimens was 38%. In contrast, 95% of specimens that were frozen for 1 week and mixed post-thaw retained the MA levels found prior to freeze. In the 5% of specimens in which MA was not retained, an approximately 50% reduction in MA levels was found. Repeat measurements, vigorous mixing and analysis of the pellet did not allow the authors to determine where the MA was lost. The authors conclude that well mixed frozen urine specimens can be used for MA analysis, but in a small percentage of cases this will lead to falsely low results.

   Biospecimens

   • Bodily Fluid - Urine

   Preservative Types

   • Frozen
   • None (Fresh)

   Diagnoses:

   • Other diagnoses

   Platform:

   Analyte	Technology Platform
   Protein	Clinical chemistry/auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage temperature	-20 degrees C
   Storage	Storage duration	1 week
   Biospecimen Aliquots and Components	Biospecimen mixing	Unmixed Inverted 3-4 times
   Biospecimen Preservation	Type of fixation/preservation	Frozen None (fresh)

   View more