Rapid blood test identifies patients at highest risk of COVID-19
What's the story
Scientists have developed a rapid blood test that can predict within a day of hospitalization which COVID-19 patients are at the highest risk of severe complications or death. This will help identify those who best benefit from specific investigational treatments. The test, described in the journal JCI Insight, measures levels of mitochondrial DNA, a genetic material that resides inside the energy factories of cells.
Test development
Better tools are needed to evaluate COVID-19
According to researchers at Washington University School of Medicine, mitochondrial DNA spilling out of cells and into the bloodstream indicates that a type of violent cell death is taking place. "Doctors need better tools to evaluate COVID-19 patients as early as possible because many treatments are in short supply, and some patients can get better without intensive treatments," said study co-author Andrew E. Gelman.
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Tissue damage might be one reason for death spiral
"We need to understand why some patients, irrespective of their ages or underlying health, go into this hyper-inflammatory death spiral. Our study suggests that tissue damage may be one cause since the mitochondrial DNA that is released is itself an inflammatory molecule," Gelman said.
Virus and DNA
New test may benefit patients who need specific investigational treatments
Viruses are known to cause a type of tissue damage called necrosis that is a violent, inflammatory response to the infection, the researchers said. This may lead to cells breaking open and releasing their contents, including mitochondrial DNA. The new test could help predict disease severity and act as a tool to design better clinical trials, identifying patients who benefit from specific investigational treatments.
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Anecdotal evidence of necrosis in lung, heart, and kidney
"In COVID-19 patients, there has been anecdotal evidence of necrosis in lung, heart, and kidney. We think it's possible that measures of mitochondrial DNA in the blood may be an early sign of this type of cell death in vital organs," Gelman explained.
Elevated DNA levels
Elevated mitochondrial DNA levels increase chances of death
It was noted that mitochondrial DNA levels were about tenfold higher in patients with COVID-19 who developed severe lung dysfunction or eventually died. "Those with elevated levels were almost six times more likely to be intubated, three times more likely to be admitted to the ICU, and almost twice as likely to die compared with those with lower levels," the scientists said.
Assessment
Study did not include patients' age or sex
In the study, the researchers assessed 97 patients with COVID-19, measuring their mitochondrial DNA levels on the first day of their hospital stays. They found that mitochondrial DNA levels were much higher in patients who eventually were admitted to the ICU, intubated, or died. The study was held independently of a patient's age, sex, and underlying health conditions.
Efficiency
The test returns results in less than an hour
According to the scientists, the test is quick to perform, returning results in less than an hour, and uses the same machinery that processes the standard PCR test for COVID-19. They said the method allows mitochondrial DNA levels to be quantified directly from a patient's blood sample without requiring intermediate steps to extract the DNA from the blood.
COVID-19 test
Certain verifications needed before applying for approval
They said the test could also predict outcomes as well as, or better than, existing markers of inflammation currently measured in patients hospitalized with COVID-19. The researchers hope to verify that the test is accurate in a larger multi-center trial before applying for approval from the US Food and Drug Administration.