From the Research
The Galleri test is a moderately accurate multi-cancer early detection blood test, but its accuracy varies depending on the cancer type and stage, and it should be used under healthcare provider guidance as part of a comprehensive approach to cancer detection. The test has a specificity of about 99.5%, meaning it has a low false positive rate, but its sensitivity varies significantly depending on the cancer type and stage, ranging from around 18% for stage I cancers to over 90% for later-stage cancers 1. The test works by detecting cell-free DNA shed by tumors into the bloodstream and analyzing methylation patterns to identify cancer signals and predict the cancer's origin.
Some of the key points to consider when evaluating the Galleri test include:
- The test is meant to complement, not replace, recommended cancer screenings like mammograms or colonoscopies 2
- If you receive a positive result, additional diagnostic testing is necessary to confirm the presence of cancer
- The test is most appropriate for adults with elevated cancer risk factors and should be used under healthcare provider guidance as part of a comprehensive approach to cancer detection 3
- The test's accuracy and effectiveness are still being studied and validated in ongoing clinical trials, such as the NHS-Galleri trial 2
It's also important to note that the Galleri test is not a replacement for regular cancer screenings, and individuals should continue to follow recommended screening guidelines for their age and risk factors. Additionally, the test's high specificity means that false positives are unlikely, but false negatives can still occur, particularly for early-stage cancers 4.
Overall, the Galleri test has the potential to be a useful tool in the early detection of cancer, but its limitations and variability in accuracy must be carefully considered, and it should be used in conjunction with other screening methods and under the guidance of a healthcare provider 5.