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Background: Urothelial carcinoma of the upper tract (UTUC) is relatively rare. Urine cytology has been used in the diagnosis and surveillance of UTUC but its utility is not well established. Another method of UTUC detection is via endoscopic biopsy which itself can be limited due to inadequate sampling. Our study aims to explore the efficacy of urine cytology alone and in combination with endoscopic biopsy results in detecting UTUC. Design: We searched our pathology database for cases with both urine cytology specimen and subsequent histologic followup including endoscopic biopsies, ureterectomy, nephrectomy or nephroureterectomy over a 10 year period. Urine cytology and biopsies done concurrently or within 6 months follow-up are included in the study and the highest degree of abnormality was selected if multiple specimen available. For cases with both biopsies and surgical specimen diagnoses, the final diagnosis from surgery was used. Results: 154 cases of confirmed UTUC were included in the study. Among them, urine diagnoses of suspicious or positive for malignancy were made in 106 cases (69%): 7 cases were low grade UC (LGUC) and 99 cases were high grade UC (HGUC) upon surgical pathology evaluation. 32/154 cases (21%) were atypical urothelial cells (AUC) on cytology, among which 27 had confirmed HGUC and 5 cases had LGUC on surgical pathology. 16/154 urine cytology cases (10%) were negative: 11/16 had HGUC and 5/16 cases had LGUC in the concurrent or follow-up biopsies or surgery. The sensitivity for abnormal urine cytology was 89.6% for detecting UTUC. We also compared the urine cytology and endoscopic biopsies (within 6 months) in detecting UTUC. There are 62 cases are positive for both methods. Four cases show positive urine but negative biopsy, and 1 with negative urine but positive biopsy (HGUC). The sensitivity for combined urine cytology and biopsy is slightly higher for one method alone. Conclusions: Urine cytology is highly sensitive for detecting UTUCespecially for HGUC. Combining urine cytology and endoscopic biopsy results increases the sensitivity for detecting UTUC and should therefore be recommended for clinical practice