Genetic Test Flaw Puts Thousands at Risk for Cancer

A malfunction in a genetic test designed to detect mutations linked to increased risks of breast and ovarian cancer may have given false-negative results to some women. The Israeli Ministry of Health reported a glitch in a BRCA1 gene mutation test kit from the company Gamidor, raising concerns about inaccurate negative results. Following the discovery, over 90,000 tests conducted with the faulty kit were re-examined. Gamidor, along with genetic institutes and laboratories, identified approximately 100 samples that might have received incorrect negative results. The issue has since been rectified.

Genetic institutes and laboratories will contact individuals whose tests are suspected of being inaccurate in the coming days. Those identified as potentially affected will be invited for a follow-up blood test if necessary. The Ministry of Health emphasized that only those with potential inaccuracies will be contacted, and others who underwent the test do not need to reach out.

The affected test, known as a nanochip test, screens for common genetic changes in the BRCA1 gene. Carrying mutations in this gene significantly elevates the lifetime risk of developing breast cancer (60-80% compared to 13% for non-carriers) and ovarian cancer (20-60% compared to 1.5% for non-carriers). These mutations are more common in women of Ashkenazi Jewish descent and have also been identified in the Ethiopian population. The test, performed on a blood sample, is recommended for women aged 25 and older after medical consultation and was added to Israel's national health basket in 2021, initially for Ashkenazi women and later extended to those of Ethiopian descent.

This is not the first time Gamidor's genetic screening kits have experienced issues. In September of the previous year, a malfunction was reported in their kit for Duchenne muscular dystrophy. A month later, the Ministry of Health updated on a BRCA mutation screening test, also from Gamidor, after a woman who received a negative result was later diagnosed with breast cancer. Two additional malfunctions in Gamidor's extended genetic screening kit for women planning pregnancy were discovered in November 2025.

Karin Aharon, co-founder of the "Good Genes - Hereditary Cancer Carriers Community" association, welcomed the transparency but highlighted the personal impact on women who received misleadingly reassuring results. She stated that these women, at significantly higher risk, were not receiving the necessary monitoring. The association has requested the Ministry of Health to clarify the timeframe of the faulty kit's operation and the control mechanisms to prevent future occurrences.