Inter-Method Agreement of a Laboratory-Developed Qualitative CMV PCR Assay Across Multiple Non-Plasma Clinical...

Area of Science:

• Molecular diagnostics
• Virology
• Clinical chemistry

Background:

• Evaluating the performance of laboratory-developed tests (LDTs) is crucial for clinical diagnostics.
• Cytomegalovirus (CMV) DNA detection is important in various clinical settings.
• Non-plasma specimen types present unique challenges for molecular assays.

Purpose of the Study:

• To assess the inter-method agreement of an in-house qualitative CMV real-time PCR assay.
• To compare the assay's performance against a commercially available comparator assay.
• To evaluate CMV DNA detection across diverse non-plasma clinical specimens.

Main Methods:

• Prospective comparative study involving 186 clinical specimens.
• Analyzed bronchoalveolar lavage fluid (BALF), stool, urine, colonoscopic biopsy, amniotic fluid, and intraocular fluid.
• Used an in-house qualitative PCR assay and a commercial kit (artus® CMV QS-RGQ), assessing agreement with PPA, NPA, OPA, and Cohen's kappa coefficient (κ).

Main Results:

• Substantial overall inter-method agreement (κ = 0.66) was observed across all specimen types.
• Highest agreement was found in stool, urine, and invasive specimens.
• Lower agreement in BALF samples suggests potential matrix-related analytical variability.

Conclusions:

• The in-house qualitative CMV PCR assay demonstrated substantial analytical concordance with the comparator assay.
• Findings underscore specimen-specific variability in CMV DNA detection.
• The study confirms analytical agreement between two molecular assays, not clinical diagnostic accuracy or viral load quantification.