Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

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Sample Processing and Stability for Urine Biomarker Studies.

Author(s): Chang C, Obeid W, Thiessen-Philbrook H, Parikh CR

Publication: J Appl Lab Med, 2021, Vol. 6, Page 1628-1634

PubMed ID: 34414423 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   In this study the levels 18 urinary biomarkers were compared between in urine specimens that were frozen immediately after centrifugation (control) and urine that was stored for 48 h at 4°C or room temperature after centrifugation, or frozen without centrifugation. Urine was collected via a foley catheter from 20 patients with one or more risk factors for acute kidney injury 48 h after heart surgery. Urine specimens were either immediately aliquoted and frozen at -80°C, or centrifuged at 5000 g at 4°C and then were either promptly frozen (control) or stored for 48 h at 4°C or 25°C before freezing at -80°C. Dipsticks were used to measure levels of IFN-ɣ, IL-10, IL-12p70, IL-13, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-18, TNF-α, KIM-1, MCP-1, YKL-40, EGF, NGAL, OPN, and UMOD.  The authors state significance was defined “by visual evaluation of these figures along with the slope of the best fit line, CCC, and the mean/median bias.”

   Summary of Findings:

   Levels of IL-12p70 and IL-70 were higher in urine specimens that were stored after centrifugation for 48 h at room temperature or 4°C or directly frozen at -80°C (uncentrifuged) compared to urine specimens that were frozen immediately after centrifugation (control). Further, only weak to modest correlations in IL-12p70 and IL-70 levels were observed between control urine and urine stored for 48 h at room temperature (r=0.577 and r=0.538, respectively) or 4°C (r=0.380 and r=0.427, respectively) or urine specimens that were frozen without centrifugation (r=0.168 and r=0.267, respectively).  Urine that was stored for 48 hours at room temperature after centrifugation had higher levels of IFN-ɣ, IL-10, TNF-α, and IL-1β and lower levels of UMOD, OPN, and IL-18 than control urine, but correlations between the two conditions ranged from strong (OPN r=0.811, IL-1β r=0.916, TNF-α r=0.736, and UMOD r=0.868) to modest (IFN-ɣ r=0.620 and IL-10 r=0.648) to weak (IL-18 r=0.317).  Uncentrifuged frozen urine had higher levels of IL-2, IFN-ɣ, IL-10, TNF-α, IL-1β, and UMOD than control urine; however, with the exception of IL-2 and IFN-ɣ (r=0.498 and r=0.629, respectively), levels were strongly to very strongly correlated between the two conditions. Levels of IL-6, IL-8, KIM-1, MCP-1, YKL-40, EGF, and NGAL were comparable to and strongly correlated with levels in control urine when urine specimens were stored for 48 h at room temperature or 4°C after centrifugation, or frozen immediately without centrifugation.

   Biospecimens

   • Bodily Fluid - Urine

   Preservative Types

   • Frozen

   Diagnoses:

   • Diabetes Type 2
   • Cardiovascular Disease

   Platform:

   Analyte	Technology Platform
   Protein	Clinical chemistry/auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Aliquots and Components	Centrifugation	Not centrifuged Centrifuged
   Storage	Storage conditions	Centrifuged Uncentrifuged
   Storage	Storage temperature	Room temperature 4°C
   Storage	Storage duration	0 h 48 h

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