Quantification and identification of polyomavirus DNA in blood and urine of renal transplant recipients

A cohort of 201 kidney transplant recipients (KTR) including 7 patients with evidence of renal function deterioration (as defined by creatinine levels >20% over baseline values) was analyzed for polyomavirus DNA in blood and urine samples by a new quantitative polymerase chain reaction method. Of 201 patients, 14 (6.9%) were positive for polyomavirus DNA in blood (median level, 500 copies per milliliter of blood) including all 7 patients with renal function deterioration. Polyomavirus DNA detection in blood for diagnosis of renal function deterioration in KTR showed a sensitivity of 100% and a specificity of 96%, whereas positive and negative predictive values were 50% and 100%, respectively. Diagnostic value of decoy cells detection and polyomavirus DNA quantification in urine samples was negligible.