Genetic blood tests for cancer screening — also called liquid biopsies or genetic cancer screening tests — are generally not harmful to humans. However, there are some important pros and cons to understand.
Minimally Invasive:
These tests usually involve drawing a small amount of blood — similar to a routine blood test.
No Radiation or Surgery:
Unlike CT scans or biopsies, there’s no exposure to radiation or need for tissue removal.
No Direct Physical Risk:
The test itself doesn't change your DNA or increase cancer risk.
False Positives:
The test may detect something that looks like cancer but isn’t — leading to anxiety or unnecessary further testing.
False Negatives:
The test might miss a cancer, giving a false sense of security.
Uncertain Findings:
You might learn you have a genetic variant that’s uncertain or only slightly increases your risk, which can cause confusion or stress.
Psychological Impact:
Learning you carry a high genetic risk (e.g., BRCA1 or BRCA2 mutation) can cause anxiety, depression, or lead to difficult decisions (like preventive surgery).
Privacy Concerns:
Genetic information is sensitive. Although there are legal protections in many countries (like GINA in the U.S.), concerns remain about insurance or employment discrimination.
You have a family history of cancer (like breast, ovarian, or colon cancer).
You're part of a population at higher genetic risk.
A doctor recommends it as part of a broader screening or diagnostic plan.
Physically, the test is safe — just a blood draw.
Emotionally and psychologically, the results can be complex.
Best done with genetic counseling before and after, to understand the results and implications.