AMP Publishes Best Practice Guidance for Slice Testing Approach in Diagnostics

As the discovery of genes linked to a variety of inherited conditions accelerates, clinical labs are finding it increasingly challenging to keep up with multiple assays dedicated to specific disease-related gene panels. To streamline this process, labs are adopting a 'slice testing' approach that employs a comprehensive capture backbone to analyze data pertinent to a specific gene set. Like conventional disease-focused panels, slice testing sequences a wide array of genes but narrows down the analysis to a pre-selected group of pertinent genes. This method combines the benefits of high-quality gene panels with the wider scope and adaptability of exome sequencing.

The Association for Molecular Pathology (AMP, Rockville, MD, USA) has released a detailed report that explores the unique aspects of employing a slice testing strategy for diagnostic purposes. This includes the intricacies of gene selection, analytical performance, coverage, quality, and data interpretation. The report consolidates expert consensus recommendations and findings from an AMP-conducted survey comparing the slice testing method with conventional static gene panels and extensive exome analyses.

Image: Slice testing is a relatively new practice that enhances flexibility in germline genetic testing for clinical laboratories (Photo courtesy of 123RF)

The AMP Whole-Exome Sequencing Standards Working Group was formed to examine prevailing laboratory practices and formulate preliminary best practice guidelines for germline slice testing via exome approaches. These guidelines draw from a comprehensive review of current scientific literature, detailed survey results, and the firsthand knowledge of the Working Group's experts. The published manuscript, titled “Slice Testing - Considerations from Ordering to Reporting: A Joint Report of the Association for Molecular Pathology, College of American Pathologists, and National Society of Genetic Counselors,” provides an in-depth look at the practicalities, potential, and limitations of slice testing for both laboratories and clinical practitioners. These expert consensus recommendations serve as a resourceful guide, though they are not to be interpreted as a restrictive list.

“As with any emerging clinical methodology, information on slice testing is limited. This new report summarizes the current collective state of knowledge and assists clinical laboratory professionals with best practice guidance for test design and utilization,” said Susan Hsiao, MD, Ph.D., 2023 AMP Clinical Practice Committee Chair. “AMP will continue to work together with organizations like CAP and NSGC to monitor real-world evidence, share our members’ expertise, and provide the broader laboratory community with a menu of guideline resources to help improve clinical practice.”

“Slice testing is a relatively new practice that enhances flexibility in germline genetic testing for clinical laboratories and providers,” said Rong Mao, MD, Chair of the AMP Whole-Exome Sequencing Standards Working Group. “AMP will continue to reassess and modify our best practice guidance as new data and/or reference materials become available.”

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