Comparative Evaluation of Three Nucleic Acid-Based Assays for BK Virus Quantification

Area of Science:

• Virology
• Molecular Diagnostics
• Transplantation Medicine

Background:

• BK virus (BKV) reactivation poses a significant risk for renal and hematopoietic stem cell transplant recipients.
• Standardized and validated assays are needed for effective BKV monitoring in clinical settings.
• Current commercial BKV assays lack comprehensive performance evaluation.

Purpose of the Study:

• To evaluate and compare the performance of three commercial real-time PCR kits: R-gene, GeneProof, and RealStar.
• To assess their accuracy in quantifying BK virus (BKV) in plasma and urine samples across different genotypes.
• To determine the correlation of these assays with a reference laboratory's results.

Main Methods:

• Comparative performance evaluation of R-gene, GeneProof, and RealStar real-time PCR kits.
• Testing on plasma and urine specimens from patients with various BKV genotypes.
• Correlation analysis using Spearman's Rho and Bland-Altman methods against a reference laboratory and a BKV panel.

Main Results:

• High qualitative global agreement (96.8%) among the three assays.
• Strong correlation (Spearman's Rho 0.92-0.98) between assays for plasma and urine samples.
• RealStar showed higher sensitivity, particularly for BKV subtype Ib1; greatest variability noted in subtype Ib2.

Conclusions:

• The R-gene, GeneProof, and RealStar real-time PCR systems demonstrate reliable and comparable performance for BKV quantification.
• These assays are suitable for screening BKV replication in transplant recipients.
• Further investigation into assay variability for specific BKV subtypes may be warranted.