The Stability of Urine Chemistry Strip Parameters Stored in BD Vacutainer® UAP Preservative Tubes

Abstract Objectives: Urinalysis requires that urine specimens maintain their biochemical and physical integrity from collection through to analysis. Delays between sample collection and laboratory processing can introduce variability due to chemical and cellular degradation. Design & Methods: This study evaluated the stability of 11 urine strip parameters and two ratios in 100 samples preserved in BD Vacutainer® UAP tubes and stored at room temperature over a 48-hour period, using UC-3500 automated urine chemistry analyzer developed by Sysmex (Japan). Parameters analyzed included colour, appearance, pH, specific gravity, haemoglobin, leukocyte esterase, nitrites, proteins, ketones, albumin, creatinine, protein-to-creatinine ratio (PCR), and albumin-to-creatinine ratio (ACR). Samples were analyzed at baseline (0 hours), 24 hours, and 48 hours. Results: Data showed minimal changes in all parameters except for a clinically acceptable increase in pH from 5.87 to 6.15 (Standard deviation (SD): 0.11). Specific gravity remained stable from 1015 to 1016 (SD: 0.8). Haemoglobin and leukocyte esterase slightly decreased in 6 samples, reflecting a minor degradation. Colour, appearance, albumin, creatinine, PCR, and ACR remained unchanged over time. Conclusion: These findings support the efficacy of BD Vacutainer® UAP preservative tubes in maintaining urine sample stability at room temperature for up to 48 hours, thus highlighting their utility in clinical settings where immediate processing is impractical.