One of the arguments for U.S. Food and Drug Administration oversight over laboratory-developed tests (LDTs) involves the need for greater assurances regarding the quality and consistency of these tests. A brief report published Dec. 14 in JAMA Oncology may allay some of these concerns. A study of close to 7,000 College of American Pathologists proficiency testing samples found that LDTs and FDA-approved companion diagnostics (FDA-CDs) had similarly high accuracy for detecting variants in three oncology-related genes—BRAF, EGFR, and KRAS. However, the researchers found that more than 60 percent of laboratories report modifying the intended use of FDA-CDs, essentially making them LDTs. The researchers compared analytical validity and associated preanalytic practices for 6,897 proficiency testing responses. Combined, both LDTs and FDA-CDs exceeded 97 percent accuracy across all the samples. For BRAF mutations, LDTs outperformed FDA-CDs with a 96.6 percent acceptable rate while FDA-CDs results were significantly lower at 93.0 percent. The researchers attributed this difference primarily to analysis of the BRAF p.V600K mutation (88.0 percent for LDTs versus 66.1 percent acceptable rate for FDA-CDs). For EGFR, LDTs performed slightly, but significantly, less well than the FDA-CDs (97.6 percent acceptability for LDT versus 99.1 percent for FDA-CDs). This discrepancy was driven by […]