“The Food and Drug Administration on Monday approved Guardant Health’s blood test, called Shield, to screen for colon cancer. The test isn’t meant to replace colonoscopies, but is generating enthusiasm among doctors who say it has the potential to boost the dismal rate of screenings for the second-highest cause of cancer death in the United States…

Research published in March showed Shield was 83% effective in finding colorectal cancers. It works by detecting the DNA that cancerous tumors release into the bloodstream.

It’s most effective in finding later-stage cancers, when tumors release more of that DNA. The study found that Shield only detected 13% of earlier-stage polyps.

The test would need to be given at least every three years, starting at age 45 — the same age it’s recommended to begin colorectal screening.

A positive test isn’t necessarily a diagnosis. If the results indicate cancer is present, patients would still need a colonoscopy so doctors can see where tumors are and how far they’ve progressed.”

From NBC News.