Stability of common analytes in urine refrigerated for 24 h before automated analysis by test strips.
Author(s): Froom P, Bieganiec B, Ehrenrich Z, Barak M
Publication: Clin Chem, 2000, Vol. 46, Page 1384-6
PubMed ID: 10973869 PubMed Review Paper? No
Purpose of Paper
Conclusion of Paper
Studies
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Study Purpose
The purpose of this study was to determine the effect of refrigeration for 24 h on the stability of 6 common urine analytes measured by autoanalyzer. The precision of the tests was also examined through repeat testing within 1 h.
Summary of Findings:
Refrigeration of the specimen for 24 h did not impact the stability of nitrates, ketones, or glucose. Refrigeration led to false-negative test results for red blood cells (p<0.05), and a 25% false negative result rate for leukocytes esterase (p<0.005). Proteinuria at low concentrations (less than 5,000 mg/L) showed an increase in false positive test results (P<0.05) after refrigeration. While the tests for nitrates, ketones, red blood cells and leukocyte esterase showed a high degree of precision, glucose and proteinuria tests led to false results at lower concentrations (less than 10,000 mg/L and less than 5,000 mg/L, respectively). The glucose and proteinuria results may have been affected by a small sample size in the high concentration categories. In conclusion, automated urinalysis is generally precise but results may be altered if specimens are stored for 24 h.
Biospecimens
Preservative Types
- None (Fresh)
- Other Preservative
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Carbohydrate Clinical chemistry/auto analyzer Small molecule Clinical chemistry/auto analyzer Protein Clinical chemistry/auto analyzer Cell count/volume Hematology/ auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Storage duration 0 h
24 h
Biospecimen Preservation Type of fixation/preservation Refrigeration
None (fresh)