An international survey of 86 genetic testing labs showed inconsistent protocols and standards for analyzing the BRCA1 or 2 cancer susceptibility genes and their variations. The results were reported in NPJ Genomic Medicine.
A majority (93%) used modern, next-generation sequencing that allows for simultaneous screening of multiple genes in a single test. However, six labs used Sanger sequencing, an older approach used before more advanced techniques were available.
After genes had been sequenced, the labs also differed in their analysis approach, including the extent of variant confirmation, whether non-coding DNA regions were sequenced, and the techniques used to detect large genomic rearrangements that could predict future cancer risk.
The researchers noted that based on which lab was used, BRCA test results could have different levels of accuracy and some variants might be missed. They called for the development of global best-practice guidelines for BRCA testing to ensure consistency regardless of lab used.