Blood tests are booming as a way to diagnose a variety of diseases.
This year, the FDA approved two blood tests to detect colon cancer, a blood test was developed to diagnose Alzheimer's, and a blood test was found to accurately predict cardiovascular events in women up to 30 years in advance.
More health systems and private companies are exploring the possibilities of blood tests this year.
Blood tests
Here are some of the recent news around blood tests Becker's has covered in the past year:
- A single blood test was found to predict cardiovascular events in women over a 30-year period.
- Swedish researchers found a blood test can diagnose Alzheimer's disease with a 91% accuracy — about 20% higher than dementia specialists.
- The FDA approved Guardant Health's Shield blood test for colon cancer screening.
- Renton, Wash.-based Providence is launching a first-of-its-kind study to examine the real-world implementation of multi-cancer early-detection blood tests.
- FDA advisers recommended the approval of Guardant Health's blood test to detect colon or rectal cancers — but it also raised some concerns that Guardant's test was not as accurate as colonoscopy and noted Shield detected only 13% of advanced adenomas, or precancerous tumors.
- Seattle-based Fred Hutchinson Cancer Center researchers found a blood test could detect colorectal cancer with 83.1% accuracy. The blood tests had a similar accuracy rate as at-home stool tests but are not as sensitive as a colonoscopy, researchers said.
- Minneapolis-based Allina Health Cancer Institute launched a first-of-its-kind clinical trial using artificial intelligence and a simple blood draw to find and diagnose breast cancer.
- Results from a pilot study led by New York City-based Memorial Sloan Kettering Cancer Center suggest that a single blood test may be able to detect the presence of 50 different cancer types.
- The Prostate Cancer Foundation released new guidelines for prostate-specific antigen-based screening in Black men, including using PSA blood tests as the first-line method of detection.
- The CDC on Jan. 18 issued updated guidance for clinicians regarding exposure to per-and polyfluoroalkyl substances, urging them to consider a patient's individual history and possible exposure to the chemicals and to order blood tests as needed to detect both recent and past exposures.
Blood tests are gaining popularity and in some cases appear to be a new avenue for better diagnosis. However, in cancer, criticism has arisen that throws doubt onto the accuracy of blood tests for cancer.
Criticism
Four years ago, a study found that cancer has unique microbial signatures that would allow a blood test to diagnose cancer. The research has been cited more than 600 times. Dozens of groups have based new work on the data and even the private sector has taken notice, with several companies attempting to create blood screening tests.
But in June, the paper was retracted following criticism from other scientists who brought up issues with its methodology and findings. Skeptics say that some of the microbes flagged as components of cancer signatures weren't known to exist in humans.
The "near-perfect association between microbes and cancer types reported in the study is, simply put, a fiction," an analysis published October 2023 in the journal mBio stated. The analysis also found the researchers incorrectly deployed a genomic tool to match tumor data to microbial sequencing.
"It wasn't a close call," Steven Salzberg, PhD, a computational biologist at Baltimore-based Johns Hopkins University, told the Journal. "This data is completely wrong."
When Nature retracted the study, it cited the above critiques and noted that the paper's authors agreed with its retraction. But the retraction has created a ripple effect, with many other studies having to correct or retract their work due to the original piece's flawed science.