Analysis of diagnostic concordance between urinary sediment and kidney biopsy

Abstract

Introduction

The microscopic examination of urinary sediment, an integral part of urinalysis, is a valuable diagnostic tool in nephrology. Its correct execution and interpretation are crucial in the initial diagnostic approach and the clinical follow-up of various nephropathies, with particular relevance in the suspicion of glomerular diseases. The utility of this analysis in strongly suggesting the glomerular origin of hematuria provides significant diagnostic guidance, acting as a “liquid biopsy” whose formed elements can directly correlate with renal histology findings.

Objectives

To evaluate the correlation between renal histological findings and the presence of dysmorphic hematuria in the urinary sediment, stratifying the analysis based on the detection of acanthocytes and/or red blood cell casts.

Materials and methods

The cohort consisted of 200 women (66.7%) and 100 men (33.3%). The presence of acanthocytes and/or red blood cell casts (Group D1) was significantly associated with a higher probability of PG (OR 12; 95% CI: 9.6–20.5; p = 0.001). In contrast, dysmorphic hematuria without these specific elements (Group D2) was associated with a higher probability of NPG (OR 6; 95% CI: 2.4–8.3; p = 0.001).

Results

The urine samples corresponded to 200 women (66.6%) and 100 men (33.3%). The presence of acanthocytes (D1) in proliferative glomerular diseases (GP) was 12 times more frequent compared to non-proliferative diseases (NPG) (OR 12; 95% CI: 9.6–20.5; p = 0.01). The presence of red blood cells is 15 times more frequent in GP (OR 15; 95% CI: 9–40.9). Patients with non-acanthocyte hematuria (D2) are 6 times more frequent in an NPG (OR 6; 95% CI: 2.4–8.3; p = 0.01).

Conclusion

The presence of dysmorphic hematuria is a useful marker for detecting glomerular disease, although its moderate sensitivity highlights the need for complementary diagnostic tests. In this cohort, the combination of acanthocytic dysmorphic hematuria and the presence of at least one red blood cell cast demonstrated high specificity for diagnosing proliferative glomerulopathy. However, for an accurate diagnosis and prognosis, renal biopsy remains indispensable.