The role of urine cytology for 'decoy cells' as a screening tool in renal transplant recipients.

OBJECTIVE

To determine the role of urine cytology for 'decoy cells' as a screening tool for polyomavirus type BK (BKV) infection in renal transplant recipients.

STUDY DESIGN

This was a prospective cohort study of patients undergoing renal transplantation between 2006 and 2010.

RESULTS

A total of 442 patients underwent urine cytology for decoy cells, 27.8% underwent 1 examination only and 72.2% more than one. Of the 1,713 examinations reviewed, 426 (24.9%) were positive and 785 (45.8%) were negative for 'decoy' cells, 380 (22.2%) showed degenerated tubular cells and 122 (7.1%) were unsatisfactory for analysis. Urine cytology was found to have a specificity of 68.5%, a sensitivity of 84.6%, a positive predictive value of 21.2%, a negative predictive value of 97.8% and an overall accuracy of 69.9%. The incidence of polyomavirus nephropathy among the patients investigated was 11.8%. Of the 442 patients, 32 (7.2%) had graft loss, which was attributed to BKV nephropathy in 2 (6.2% of the 32).

CONCLUSIONS

Urine cytology is an effective screening method for monitoring renal transplant patients, with high sensitivity and a high negative predictive value, and can therefore be used routinely in the follow-up of renal transplant patients.