Stability of urine specimens stored with and without preservatives at room temperature and on ice prior to urinalysis.
Author(s): Ercan M, Akbulut ED, Abuşoğlu S, Yılmaz FM, Oğuz EF, Topçuoğlu C, Öztekin V, Boğdaycıoğlu N
Publication: Clin Biochem, 2015, Vol. 48, Page 919-22
PubMed ID: 26025772 PubMed Review Paper? No
Purpose of Paper
This paper investigated the stability of clinical chemistry and microscopy parameters during storage of urine with or without preservatives on ice for up to 8 h and at room temperature for up to 72 h.
Conclusion of Paper
Greater than 80% agreement with 0 h results was observed for most analytes when urine was stored with or without preservatives for up to 8 h on ice or at room temperature in preservative tubes for 72 h, but lower concordance was observed for WBC clumps and amorphous crystals in specimens stored for 8 h on ice without preservative, WBC counts in specimens stored on ice for 4 or 8 h with preservative, and RBC and WBC counts in specimens stored with preservative at room temperature.
Studies
-
Study Purpose
This study investigated the stability of clinical chemistry and microscopy parameters during storage of urine with or without preservatives on ice for up to 8 h and at room temperature for up to 72 h. First-void specimens were collected from 48 patients in an outpatient clinic, but patient diagnosis was not specified. Specimens were divided into BD VacutainerPlus Urinalysis preservative tubes containing chlorohexidine and into polystyrene tubes. Specimens in both tube types were refrigerated and analyzed after 4 and 8 h and specimens in preservative tubes were also stored at room temperature and analyzed after 4, 8, 24, or 72 h. Analysis was performed using iChem VELOCITY Strips on an iChem VELOCITY Urine Chemistry System, iQ200 SPRINT.
Summary of Findings:
When urine was stored at room temperature for up to 72 h in preservative tubes, most analytes displayed greater than 80% agreement with results at 0 h, but RBC counts at 72 h were 79.2% concordant with those at 0 h and WBC counts at 24 h and 72 h were only 70.8% and 77.1% concordant, respectively. Interestingly, when specimens were stored in preservative tube on ice packs the WBC counts only displayed 60.4% and 52.1% agreement with the 0 h results after 4 h and 8 h, respectively. When urine was stored without preservatives on ice packs, agreement with 0 h results for WBC clumps and amorphous crystals was 77.1% and 79.1%, respectively after 8 h of storage, but greater than 80% agreement with 0 h results was found for all other analytes after storage up to 8 h. Agreement of greater than 80% was achieved for glucose, protein, blood, nitrites, ketones, leukocyte esterase, pH, specific gravity, epithelial cells, casts, bacterial cells yeast, CaOx crystals, and uric acid regardless of storage condition.
Biospecimens
Preservative Types
- Other Preservative
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Carbohydrate Clinical chemistry/auto analyzer Cell count/volume Clinical chemistry/auto analyzer Protein Clinical chemistry/auto analyzer Cell count/volume Light microscopy Small molecule Clinical chemistry/auto analyzer Morphology Light microscopy Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Preservation Type of fixation/preservation Refrigeration
Chlorhexadine
Storage Type of storage container BD Vacutainer®Plus Urinalysis preservative tubes
Polystyrene tubes
Storage Time at room temperature 0 h
4 h
8 h
24 h
72 h
Storage Storage duration 0 h
4 h
8 h
Storage Storage temperature Room temperature
On ice