Long-term urine biobanking: storage stability of clinical chemical parameters under moderate freezing conditions without use of preservatives.
Author(s): Remer T, Montenegro-Bethancourt G, Shi L
Publication: Clin Biochem, 2014, Vol. 47, Page 307-11
PubMed ID: 25239781 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to determine the effects of 12 or 15 years of storage at -22°C on the measurement of 21 clinical chemistry analytes in 24 h urine specimens from healthy children.
Conclusion of Paper
Long-term frozen storage of urine significantly increased the measured osmolality, chloride, phosphate, sulfate, and pH and decreased the measured titratable acid, renal net acid excretion (NAE), oxalate and titrated organic acids.
Studies
-
Study Purpose
The purpose of this study was to determine the effects of 12 or 15 years of storage at -22°C on the measurement of 21 clinical chemistry analytes in 24 h urine specimens from 10 healthy children. Urine was frozen at -12 to -20°C and transferred to the laboratory where it was stored at -22°C. At the laboratory, specimens were thawed, mixed, aliquoted, and analyzed. Importantly the same methods/machines were used at each timepoint but with fresh reagents generally ordered from the same supplier. Total titrated organic acids, citrate and uric acid were analyzed after 12 years and creatinine, urea, osmolality, iodine, nitrogen, chloride, phosphate, sulfate, sodium, potassium, calcium, magensium, pH, titratable acid, ammonium, bicarbonate, renal NAE, oxalate, iodine and nitrogen were measured after 15 years.
Summary of Findings:
After 15 years of frozen storage, significant increases in the measured osmolality (3%), chloride (4%), phosphate (5%), sulfate (3%), and pH (2%) and decreases in the measured titratable acid (-19%) renal NAE (-7%) and oxalate (-27%) were found (p<0.05, all). Further, measured total titrated organic acids declined by 11% when stored frozen for 12 years (P<0.05). Importantly, levels before and after storage were very strongly correlated for all analytes (r=0.94-0.99) except oxalate which showed strong correlations (r=0.77).
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Normal
Platform:
Analyte Technology Platform Electrolyte/Metal Atomic absorption spectroscopy Small molecule Spectrophotometry Small molecule Clinical chemistry/auto analyzer Electrolyte/Metal Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Storage duration 0 years
12 years
15 years
Storage Freeze/thaw cycling 1 cycle
2 cycles