Table 3.

Mean percentage change in urine creatinine concentration, albumin concentration, and albumin-to-creatinine ratio after a delay in processing, by preservative use and by storage temperature

Storage ConditionMean Percentage Change (95% CI)Test for Equality of Means by Temperature
PreservativeNo Preservative
Creatinine
 4°C, 1 d−0.1% (−0.4% to 0.2%)−0.2% (−0.4% to 0.1%)0.28
 4°C, 2 d0.1% (−0.2% to 0.5%)0.2% (−0.0% to 0.4%)
 4°C, 4 d0.0% (−0.3% to 0.3%)0.3% (0.0% to 0.5%)
 4°C, 7 d0.6% (0.3% to 0.9%)1.1% (0.7% to 1.4%)
 18°C, 1 d−0.1% (−0.4% to 0.3%)0.1% (−0.2% to 0.4%)<0.001
 18°C, 2 d0.0% (−0.3% to 0.3%)0.9% (0.5% to 1.2%)
 18°C, 4 d−0.1% (−0.5% to 0.4%)1.5% (0.8% to 2.2%)
 18°C, 7 d0.2% (−0.4% to 0.9%)4.7% (3.5% to 5.8%)
 30°C, 1 d−0.5% (−0.9% to −0.2%)0.0% (−0.3% to 0.3%)<0.001
 30°C, 2 d−0.7% (−1.0% to −0.3%)1.1% (0.5% to 1.6%)
 30°C, 4 d−1.3% (−2.1% to −0.5%)1.4% (−0.3% to 3.2%)
 30°C, 7 d−2.4% (−3.4% to −1.5%)3.0% (−0.3% to 6.3%)
Albumin
 4°C, 1 d−0.3% (−1.9% to 1.2%)1.4% (−0.8% to 3.6%)0.39
 4°C, 2 d−1.5% (−3.3% to 0.2%)−0.5% (−3.2% to 2.3%)
 4°C, 4 d−0.1% (−1.5% to 1.4%)0.9% (−1.2% to 3.0%)
 4°C, 7 d0.8% (−1.2% to 2.8%)1.7% (−1.6% to 5.1%)
 18°C, 1 d0.5% (−1.5% to 2.5%)1.3% (−1.4% to 4.0%)0.06
 18°C, 2 d−0.1% (−1.6% to 1.3%)2.2% (−0.4% to 4.9%)
 18°C, 4 d1.0% (−1.0% to 3.0%)4.1% (1.2% to 6.9%)
 18°C, 7 d2.5% (0.6% to 4.3%)7.8% (4.8% to 10.8%)
 30°C, 1 d0.9% (−0.7% to 2.4%)1.6% (−1.1% to 4.4%)0.15
 30°C, 2 d1.6% (−0.1% to 3.3%)2.3% (−0.3% to 5.0%)
 30°C, 4 d3.0% (0.5% to 5.5%)5.6% (3.0% to 8.3%)
 30°C, 7 d5.1% (2.4% to 7.7%)10.3% (6.7% to 13.9%)
Albumin-to-creatinine ratio
 4°C, 1 d−0.3% (−1.9% to 1.2%)1.5% (−0.7% to 3.7%)0.42
 4°C, 2 d−1.8% (−3.6 to −0.1%)−0.7% (−3.4% to 2.0%)
 4°C, 4 d−0.3% (−1.8% to 1.2%)0.6% (−1.5% to 2.6%)
 4°C, 7 d−0.0% (−1.9% to 1.9%)0.5% (−2.7% to 3.8%)
 18°C, 1 d0.5% (−1.5% to 2.5%)1.2% (−1.5% to 3.8%)0.48
 18°C, 2 d−0.3% (−1.7% to 1.2%)1.2% (−1.4% to 3.9%)
 18°C, 4 d1.0% (−1.0% to 3.0%)2.3% (−0.4% to 5.1%)
 18°C, 7 d2.1% (0.3% to 3.8%)2.7% (−0.0% to 5.4%)
 30°C, 1 d1.3% (−0.3% to 2.9%)1.5% (−1.3% to 4.2%)0.79
 30°C, 2 d2.2% (0.4% to 3.9%)1.0% (−1.6% to 3.6%)
 30°C, 4 d4.2% (1.8% to 6.6%)3.9% (0.9% to 6.9%)
 30°C, 7 d7.4% (4.9% to 9.9%)7.0% (3.0% to 11.1%)
  • 95% CI, 95% confidence interval.