Microscopic Hematuria: A Classical Definition in a Modern Lab Era

Abstract

Purpose: This study endeavors to elucidate the diagnostic intricacies surrounding microhematuria, a prevalent indication for urological consultation. Specifically, the research seeks to assess the diagnostic value of urinalysis and cystoscopy procedures in minimizing the need for invasive cystoscopies, given the evolving landscape of technology-driven urinalysis. The primary objective is to provide nuanced insights for clinicians to optimize diagnostic pathways in cases of microhematuria. Method: In this retrospective case-control study, conducted at our university-based hospital, patient records spanning January 2017 to January 2022 were scrutinized following approval from the local ethics committee. The study focused on individuals diagnosed with microhematuria and subsequently subjected to cystoscopy and urine cytology. Exclusion criteria encompassed urinary tract infection, positive or suspicious urine cultures, urolithiasis, bladder pain syndrome/interstitial cystitis, pregnancy, and pre-existing bladder cancer. Urine analyses were carried out using the FUS-200 automatic urinalysis system. Results: Cystoscopy identified lesions in 17% of cases, leading to biopsy/endoscopic resection. Dipstick analysis revealed mean RBC/hpf values of 8.93±3.78 (24.61) for RBC+, 22.08±12.30 (52.77) for RBC++, and 763.56±1993.63 (78.08) for RBC+++. Among cytologies, 1% exhibited atypia with normal follow-up. Patients with detected lesions displayed varying pathology, with 23% benign cases and 77% urothelial carcinoma. Levels of measured RBC/hpf across tumor stages and histological grades were statistically insignificant, yet the median levels significantly differed between cases with and without lesions. The study outcomes indicate a significant difference in median RBC/hpf levels between cases with lesions present (77.38) and absent (45.66) (p=0.001). ROC analysis yielded an AUC of 0.814 (p=0.001, 95% CI 0.677-0.952). However, diagnostic value was suboptimal at lower cut-offs and appeared to be optimum within the range of 35-40 RBC/hpf. Conclusion: This study provides nuanced insights into the specificity of urinalysis in cases of microhematuria by correlating modern urinalysis results with cystoscopic outcomes, the research contributes to a refined decision-making framework for clinicians. It emphasizes the need for evidence-based guidelines in assessing microhematuria comprehensively, considering the evolving landscape of diagnostic technologies.