Molecular testing laboratories using College of American Pathologists (CAP) proficiency testing (PT) programs exhibit excellent testing performance, according to a recent reanalysis of a pilot study that was published in the Archives of Pathology & Laboratory Medicine.

“This reanalysis indicates that patients undergoing molecular testing at laboratories using CAP PT can continue to be confident that their test results are accurate,” says CAP President Emily E. Volk, MD, FCAP. “The CAP PT data are among the highest quality, demonstrating excellence in laboratory performance across the over 23,000 laboratories around the world that participate in this program.”

In this recent study, CAP next generation sequencing (NGS) PT data reliably detected genomic alterations in KRAS and NRAS genes. These genes are important for identifying the subset of colorectal cancer patients who are eligible to receive targeted therapy. Testing for RAS mutations is recommended by the National Comprehensive Cancer Network for advanced or metastatic colorectal cancer to determine eligibility for anti-EGFR therapy. NGS testing involving these genes was the focus of The Sustainable Predictive Oncology Therapeutics and Diagnostic (SPOT/Dx) quality assurance pilot study, published in 2021.

In the reanalysis, the authors showed that for the CAP PT programs the overall detection rates for the same single nucleotide and multinucleotide variants in the SPOT/Dx pilot were more than 97% and 92%, respectively. 

“This means that colorectal cancer patients receiving targeted therapy based on results of NGS testing performed by CAP-accredited and CLIA-certified molecular diagnostic laboratories using CAP PT should be confident in the accuracy of their test results,” the authors of the study concluded.

Reanalysis Addresses SPOT/Dx Limitations 

The initial SPOT/Dx pilot study was based on a limited data set of rare to neverobserved mutations at low allelic frequencies, studied over a limited time period. The study’s conclusions extrapolated results to all molecular testing, even though they did not reflect real world scenarios.

“Given these limitations and our reanalysis of the pilot, we concluded that initial SPOT/Dx pilot results are not generalizable to all molecular oncology testing and should not be used to market products or change policy affecting all molecular oncology testing,” says Neal Lindeman, MD, FCAP, one of the lead authors and a member of the CAP Molecular Oncology Committee, whose members led this reanalysis. “Furthermore, given the robust evidence of strong testing performance in clinical laboratories using CAP PT programs, there is no meaningful benefit for additional assessment from a third party on the performance of molecular testing in these laboratories.”