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Kidney Week

Abstract: TH-PO579

Urine Sediment Examination: Comparison Between Laboratory-Performed vs. Nephrologist-Performed Microscopy

Session Information

  • Pathology and Lab Medicine
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Pathology and Lab Medicine

  • 1700 Pathology and Lab Medicine

Authors

  • Fadel, Remy, Cleveland Clinic, Cleveland, Ohio, United States
  • Taliercio, Jonathan J., Cleveland Clinic, Cleveland, Ohio, United States
  • Arrigain, Susana, Cleveland Clinic, Cleveland, Ohio, United States
  • Schold, Jesse D., Cleveland Clinic, Cleveland, Ohio, United States
  • Simon, James F., Cleveland Clinic, Cleveland, Ohio, United States
  • Mehdi, Ali, Cleveland Clinic, Cleveland, Ohio, United States
  • Nakhoul, Georges, Cleveland Clinic, Cleveland, Ohio, United States
Background

Urine microscopy is a standard component of the urinalysis and one of the oldest tests in medicine. In more recent years, it is increasingly performed by automated analyzers rather than clinicians. However, we believe that urine sediment evaluation by a nephrologist continues to serve a critical role in the assessment of patients with kidney disease.

Methods

Using our Electronic Medical Records, we identified 387 adult patients with acute kidney injury that had urine microscopy with sediment analysis performed both by the laboratory and by a nephrologist within 72 hours of each other. We collected data to determine the following: number of RBCs (< 5 or > 5 HPF), number of WBCs (< 5 or > 5 HPF), presence of casts (<1 or > 1 LPF), type of casts (hyaline, fine granular, coarse granular, muddy brown, WBC and RBC casts), and presence of dysmorphic RBCs. We used Kappa statistics to evaluate agreement between automated urine microscopy versus nephrology review.

Results

The reported agreement was moderate for RBCs with 75% of samples in agreement (Kappa 0.46 – 95% CI: 0.37, 0.55), none to slight for WBCs with 72% of samples in agreement (Kappa 0.36 – 95% CI: 0.27, 0.45), and there was no agreement for casts (Kappa 0). Nephrologists detected 12 dysmorphic RBC’s (Kappa 0) while the laboratory did not detect any. Additionally, the laboratory only detected hyaline and fine granular casts, whereas nephrologists reported coarse granular / muddy brown, RBC and WBC casts.

Conclusion

Urine microscopy can provide important diagnostic information about underlying kidney disease. In our study, we report a disagreement between automated vs. nephrologist performed analysis. A nephrologist is more likely to recognize the presence of coarse granular, muddy brown, WBC and RBC casts, and dysmorphic red blood cells in urine. Nephrologist-performed UA is superior to laboratory-performed UA as correct identification of these casts carries important diagnostic and prognostic value when evaluating kidney disease.