High-sensitivity KIT D816V variation analysis by droplet digital polymerase chain reaction: The reference laboratory...

Area of Science:

• Hematology
• Oncology
• Molecular Diagnostics

Background:

• Systemic mastocytosis is a rare hematologic malignancy driven by neoplastic mast cell expansion.
• Accurate detection of KIT D816V is crucial for diagnosis and management, with guidelines recommending highly sensitive assays.

Purpose of the Study:

• To evaluate the clinical utility and sensitivity of droplet digital PCR (ddPCR) for KIT D816V detection.
• To compare the performance of ddPCR with next-generation sequencing (NGS) in a real-world setting.

Main Methods:

• A 3-year retrospective analysis of KIT D816V testing using ddPCR in a clinical laboratory.
• Comparison of ddPCR results with NGS for a subset of samples.
• Analysis of serum tryptase levels as a screening tool for KIT D816V detection.

Main Results:

• ddPCR detected KIT D816V in 14.9% of tested samples, demonstrating significantly higher sensitivity than NGS (37.6% vs. 6.0% positive).
• NGS showed 16% sensitivity and 100% specificity compared to ddPCR.
• A reduced serum tryptase threshold of 11.5 ng/mL improved sensitivity for detecting KIT D816V to 97.5%.

Conclusions:

• ddPCR provides a highly sensitive method for KIT D816V detection, outperforming NGS for myeloid malignancies like systemic mastocytosis.
• Utilizing a lower serum tryptase threshold (approximately 11.5 ng/mL) can enhance the screening and early detection of mast cell neoplasms.