(WXYZ) — In today’s health alert, advancements in blood testing offer new hope for early detection of serious diseases. The FDA approved a new blood test for colon cancer screening earlier Monday, which could improve low screening rates. And a new study has found a blood test for Alzheimer's can detect 91% of early dementia cases.
Research shows that the Shield blood test was 83% effective in identifying colorectal cancer. What it does, is detect DNA fragments released into the bloodstream by cancerous tumor cells and precancerous growths. But while it’s effective at detecting later-stage colon cancer, it’s only 13% effective at detecting early-stage precancerous growths or polyps.
That’s a key reason why this test is not intended to replace colonoscopies, which remain the gold standard. In my practice, I’ve performed hundreds of colonoscopies. Not only can I see lesions or growths, but I can also remove them during the 20-minute procedure, which helps reduce the risk of developing colorectal cancer.
Having said that, less than 60% of folks who are eligible for screening get tested. A blood test like the Shield is simpler and less invasive than a colonoscopy. However, if a person receives positive results, they’ll still need a colonoscopy to confirm if cancer is present.
What can you tell us about the Alzheimer's blood test, which was found to detect a high percentage of early dementia cases?
According to a study published in JAMA Neurology, a new blood test has shown a 91% accuracy rate in diagnosing Alzheimer’s disease among people with mild cognitive decline or early-stage dementia.
Researchers from Lund University in Sweden conducted the study with just over 1,200 participants. The average age was 74, and all were experiencing memory issues. Participants were given traditional exams, provided blood samples, and had confirmatory spinal taps or brain scans.
Now, one part of the blood test measures a protein called p-tau217—short for plasma phosphorylated tau 217—which is a key indicator of Alzheimer’s. This was combined with another blood biomarker that measures two types of amyloid proteins. The combination of the amyloid and tau tests, known as the amyloid probability score 2 or APS2 for short, was the most effective in identifying Alzheimer’s.
The test's 91% accuracy rate was significantly higher than the 61% accuracy rate of primary care doctors and the 73% rate of specialists in the study. This is truly remarkable. It’s so important to diagnose early-stage Alzheimer’s so that patients can receive effective treatment. However, more research is needed to confirm these results, so a widely available blood test for Alzheimer’s may still be some time away.
