Accuracy of urine dipstick in the detection of patients at risk for crush-induced rhabdomyolysis and acute kidney injury

Abstract

To evaluate the utility of urine dipstick test (UDT) for detecting rhabdomyolysis and acute kidney injury (AKI) due to crush injury. All the rescued victims of the Bam earthquake who had a documented urine analysis and serum creatine phosphokinase and creatinine levels during their hospitalization period were eligible to enter the study. The sensitivity and the specificity, along with the positive and negative likelihood ratios, of UDT in detecting at-risk patients for rhabdomyolysis and crush-related AKI were calculated. Urine red blood cell count of 5 or less in blood-positive UDT, as a surrogate marker for myoglobinuria, was reported in 210 (31.7%) of the total 1821 urine analyses. Blood-positive UDTs (without considering the urine red blood cell count) had a 92.5% (95% confidence interval: 79.6-98.4) sensitivity in creatine phosphokinase, with a cut-off of 15,000 (IU/l). Comparing the results of the serum creatinine level and the urine blood, analysis showed that UDT had a sensitivity and a specificity of as high as 83.3 and 56.6% in detecting high-risk patients for AKI, respectively. UDT can be considered as an early screening tool for the detection and triage of patients at risk of developing AKI because of traumatic rhabdomyolysis after mass disasters.