BK virus viral load: analysis of the requests received by the microbiology laboratory and clinical involvement of the issued results.

Automation of viral diagnosis has led to an increase of BK virus (BKV) viral load (VL) requests. The aim of this study was to assess the suitability of serum creatinine (SCr) for controlling the demand and to study the clinical characteristics of BKV infection. This is a retrospective study including patients with BKV VL request during April-July 2017. Clinical records and SCr were analyzed. Five hundred samples from 333 patients were included; 61.4% of samples were from males (55.5 ± 14.8 years), and all belonged to transplant recipients (86.4% renal). BKV VL was detectable in 40 samples (8.0%) from 23 patients (6.9%), who presented high SCr (100% vs. 90.9%, P = 0.038). Most of detectable VLs (62.5%) belonged to patients in their first year post-transplant. Six patients with detectable VL (26.1%) developed clinical manifestations, most of them (83.3%) had a first BKV VL greater than 10,000 copies/mL (P = 0.001). In conclusion, SCr would be useful to identify suitable specimens for BKV VL testing without missing cases.