Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

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Collection and storage of urine specimens for measurement of urolithiasis risk factors.

Author(s): Wu W, Yang D, Tiselius HG, Ou L, Mai Z, Chen K, Zhu H, Xu S, Zhao Z, Zeng G

Publication: Urology, 2015, Vol. 85, Page 299-303

PubMed ID: 25623670 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   This study investigated the effects of preservation with thymol, toluene, hydrochloric acid, or sodium azide and storage for up to 48 h at 4˚C or room temperature on levels of urine biomarkers in spot urine from 21 healthy patients. Specimens were aliquoted and two were stored with each preservative (thymol, toluene, hydrochloric acid, or sodium azide), two were left unpreserved, and one aliquot of each pair was stored at 4˚C and the other was stored at room temperature. All eight analytes were analyzed in unpreserved specimens and specimens preserved with thymol or toluene immediately after preservation and again after 24 and 48 h.  Specimens preserved with hydrochloric acid were not analyzed for pH and urate  and sodium azide-preserved specimens were analyzed only for pH and urate levels.  Levels of oxalate and citrate were determined by ion-exchange chromatography. Calcium, magnesium, and sodium levels were determined by atomic absorption spectrophotometer.

   Summary of Findings:

   Citrate levels were lower in specimens preserved with hydrochloric acid than in unpreserved specimens (P<0.05, all timepoints at both temperatures), but there was no effect of storage temperature or duration.  pH levels increased with increasing storage at room temperature or 4˚C, regardless of preservative (P<0.05, 0 versus 24 h at both temperatures and all preservatives). pH was significantly higher after 24 h in specimens stored at room temperature than 4˚C (P<0.05, all), regardless of preservative, and higher after 48 h in specimens preserved with sodium azide, thymol, or toluene (P<0.05, all). Preservative type, storage duration, and storage temperature had no impact on the levels of calcium, magnesium, phosphate, sodium, oxalate, citrate, or urate.

   Biospecimens

   • Bodily Fluid - Urine

   Preservative Types

   • Other Preservative
   • None (Fresh)

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Small molecule	Ion exchange chromatography
   Electrolyte/Metal	Atomic absorption spectroscopy
   Small molecule	Clinical chemistry/auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage duration	0 h 24 h 48 h
   Biospecimen Preservation	Type of fixation/preservation	Hydrochloric acid Thymol Toluene Sodium azide None (fresh)
   Storage	Storage temperature	4˚C Room temperature

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