Assessment of a four hour delay for urine samples stored without preservatives at room temperature for urinalysis

OBJECTIVES: To determine whether urine storage at room temperature for up to 2h versus 4h changes urinalysis results. DESIGN AND METHODS: We compared the rejection rate at eight different hospital laboratories and concordance of urinalysis results (n=83; two laboratories) between urines analyzed within 2h and 4h after collection. RESULTS: The rejection rate at the two hour cutoff was significantly higher as compared to the four hour cutoff. The concordance between urinalysis results was 97-100% between the two and four hour analyses. CONCLUSION: Urine may be stored for up to 4h at room temperature without significant changes to the urinalysis results.