Table 1.

Summary of published urinalysis AKI risk scores and their limitations

StudyStudy Characteristics and DataScoring SystemLimitations
Chawla et al. (2)Score created on the basis of 30 single-center patients and a panel of three blinded nephrologists and validated in another 18 patients. Interobserver agreement was 99.8%. AUC for nonrecovery was 0.79.Grade 1: No casts or RTE
Grade 2: At least one cast or RTE but <10% of LPF
Grade 3: Many casts or RTEs (between 10%–90% of LPF)
Grade 4: Sheet of muddy brown casts and RTEs in >90% of LPF
• Small sample size even with the validation cohort
• Exceedingly high interobserver agreement compared with the literature
• Only in those with established AKI
Perazella et al. (3)Validated in 197 single-center patients with acute tubular necrosis or prerenal AKI. Score ≥3 (compared with 0) was associated with 7.3 relative risk of AKI progression. AUC of 0.75 for AKI progression.0 points: No casts or RTE seen
1 point each: 1–5 casts per LPF or 1–5 RTEs per HPF
2 points each: ≥6 casts per LPF or ≥6 RTEs per HPF
• Interobserver agreement fairly low (κ of 0.47) for RTEs
• Urine microscopy performed at time of renal consultation rather than on day 1 of AKI
• Not blinded to patient’s clinical status
• Single-center data
Bagshaw et al. (1)83 patients with and without sepsis-associated AKI across two centers. Scores ≥3 had a PPV of 80% (49%–94%) and NPV of 91% (78%–96%) for AKI progression.0 points: No casts or RTE seen
1 point each: 1 cast or 1 RTE per HPF
2 points each: 2–4 casts or RTEs per HPF
3 points each: ≥5 casts or ≥5 RTEs per HPF
• Only one person scored all urine sediments
• Despite being two centers, small sample size
• May be specific to patients who are critically ill
  • AUC, area under the curve; RTE, renal tubule epithelial cells; LPF, low power field; HPF, high power field; PPV, positive predictive value; NPV, negative predictive value.