Critical study of common conditions of storage of glucocorticoids and catecholamines in 24-h urine collected during resting and exercising conditions.
Author(s): Gouarne C, Foury A, Duclos M
Publication: Clin Chim Acta, 2004, Vol. 348, Page 207-14
PubMed ID: 15369756 PubMed Review Paper? No
Purpose of Paper
This paper investigated the effects of preservation with hydrochloric acid (HCl) or EDTA and storage at room temperature or 4˚C for 24 h and the effects of storing unpreserved urine at 37˚C on levels of cortisol, cortisone, adrenaline, and noradrenaline in urine obtained after normal activity and after exercise.
Conclusion of Paper
Although levels of cortisol and cortisone were unaffected by preservation method or delayed freezing, levels of adrenaline and noradrenaline were affected by storage of unpreserved urine at room temperature or 37˚C and storage of EDTA-preserved urine at 4˚C or room temperature. The magnitude of the changes was correlated with specimen pH. The significance of the changes during storage of EDTA-preserved urine at 4˚C or unpreserved urine at 37˚C depended on exercise status. There were no effects of storage on HCl-preserved urine at room temperature or 4˚C.
Studies
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Study Purpose
This study investigated the effects of preservation with HCl or EDTA and storage at room temperature or 4˚C for 24 h and the effects of storing unpreserved urine at 37˚C on levels of cortisol, cortisone, adrenaline, and noradrenaline in urine obtained after normal activity and after exercise. Patients voided their bladder at 11:30 a.m. and then completed a prescribed 1 h exercise regime outside before lunch or continued with a normal schedule not including exercise until collection of urine in polypropylene containers 3 h after previous voiding (14:30). Urine was aliquoted and preserved to achieve 1% 6N HCl (final pH ~3.0), 2% EDTA, or left unpreserved. Aliquots of urine with each preservative were frozen immediately at -80˚C or stored for 24 h at 4 or 25˚C before freezing. Additional unpreserved aliquots were stored at 37˚C for 3 and 9 h before freezing. pH was determined using a pH meter. Levels of cortisol, cortisone, adrenaline, and noradrenaline were determined by HPLC.
Summary of Findings:
Levels of cortisol and cortisone were not affected by preservation, storage for 24 h at room temperature or 4˚C before freezing, or storage at 37˚C for 3 or 9 h before freezing, regardless of exercise status. Unpreserved and EDTA-preserved urine stored for 24 h at room temperature before freezing and unpreserved urine stored for 9 h at 37˚C had significantly lower levels of adrenaline and noradrenaline than urine that was frozen immediately, regardless of exercise status (P<0.05, all). In addition to the aforementioned differences, urine collected after normal activity had significantly lower levels of noradrenaline when preserved with EDTA and stored for 24 h at 4˚C than when unpreserved and immediately frozen (P<0.05) and urine collected after exercise had significantly lower levels of adrenaline when preserved with EDTA and stored for 24 h at 4˚C or when unpreserved and stored for 3 h at 37˚C than when unpreserved and immediately frozen (P<0.05, both). Degradation of adrenaline and noradrenaline with storage at room temperature or 37˚C was modestly to strongly correlated with the pH (r=0.66-0.72). Importantly, there was no effect of storing urine for 24 h at 4˚C or room temperature on levels or cortisol, cortisone, noradrenaline or adrenaline when urine was preserved with HCl.
Biospecimens
Preservative Types
- Other Preservative
- Frozen
Diagnoses:
- Normal
Platform:
Analyte Technology Platform Small molecule HPLC Steroid HPLC Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Preaquisition Diagnosis/ patient condition Normal activity
After 1 h exercise
Storage Storage duration 3 h
9 h
0 h
24 h
Storage Storage temperature 4˚C
25˚C
37˚C
Biospecimen Preservation Type of fixation/preservation Hydrochloric acid
EDTA
Frozen