Table 2B.

Stability of urinary biomarkers at prolonged storage at −20°C

Collection and ProcessingMean Percentage Difference (95% confidence interval of mean % difference)
KIM-1, n = 32NAG, n = 32NGAL, n = 32
Prolonged storage at −20 and −80°C
    2 yr with 3 repeat freeze and thaw cycles (−20 versus −80°C)−15.08 (−21.26 to −8.91)−8.88 (−16.03 to −1.74)−40.24 (−52.67 to −27.82)
    compared with initial biomarker levels 2 yr before at −20°C−6.75 (−16.99 to 3.49)−6.11 (−14.44 to 2.22)NA