Cutting-edge test uses DNA sequencing to yield diagnoses for some medical mysteries
A cutting-edge test is helping some doctors diagnose medical mysteries by analyzing DNA and RNA to detect a swath of viruses, bacteria, fungi and parasites.
A cutting-edge diagnostic test is helping some doctors find diagnoses for medical mysteries by analyzing DNA and RNA to detect a broad swath of viruses, bacteria, fungi and parasites, according to a pair of studies published Tuesday.
Traditional diagnostic tests are generally designed to measure specific substances such as proteins, hormones or trace amounts of genetic material. But the genomic test, developed at the University of California, San Francisco, instead extracts all the DNA and RNA present in a sample of blood, tissue or body fluid, then sequences that genetic material. It compares the sequences to a vast database of pathogens to see what matches up.
The technology is not a replacement for existing tests used to diagnose common illnesses — like those for Covid or strep throat — since it’s slower to deliver results and more expensive. But it shows promise in a particular scenario: when a patient is in the hospital with severe symptoms, but initial tests come back negative and doctors can’t figure out what’s wrong.
Already, the test has been effective at identifying the cause of neurological infections such as meningitis and encephalitis (swelling of the brain or its surrounding membranes), according to one of the new studies, published Tuesday in the journal Nature Medicine. Using samples of spinal fluid, it was able to diagnose 86% of the neurological infections it encountered out of more than 4,800 samples gathered at UCSF over a roughly seven-year period.
In 2021 and 2022, the test was able to link cases of encephalitis among transplant recipients to yellow fever in their organ donor. And last year, it helped pinpoint the cause of a meningitis outbreak among patients who had undergone surgical procedures in Mexico.
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