Background: The acute kidney injury (AKI) risk score helps detect moderate and severe AKI in the next 12-24 h. However, inappropriate urine collection may impact its results.
Aim: The aim of this study was to evaluate the stability of NephroCheck® after urine storage at different temperatures.
Methods: The urine sample was centrifuged and split into 3 tubes. One was tested as soon as possible by the laboratory. The other 2 samples were frozen at -20 and -80°C, and the NephroCheck® test was performed 8 weeks later.
Results: The mean values of the AKI risk score were 1.19 ± 0.93, 1.15 ± 1.14, and 1.20 ± 1.11 (ng/mL)2/1,000 for fresh urine, -20, and -80°C, respectively (p = 0.70). Spearman's rank correlation for -20 and -80°C versus immediate processing was strong with a rho of 0.82 and 0.98, respectively.
Conclusion: The AKI risk score was relatively stable. Urine could be collected without dry ice or liquid nitrogen and kept for up to 8 weeks with either -20 or -80°C freezing with stable NephroCheck® results.
Keywords: Acute kidney injury; Acute kidney injury risk score; Critical care; Insulin-like growth factor binding protein-7; Tissue inhibitor of metalloproteinases-2.
© 2020 S. Karger AG, Basel.