Scientists believe they have identified a blood test that could help predict which Covid-19 patients are at higher risk of becoming critically ill and dying.
Known as the Red Cell Distribution Widths (RDW) test, the test measures the range of volume and size of red blood cells.
The RDW test is usually used to diagnose various conditions such as anemia, heart disease, blood disorders, and diabetes.
However, researchers at Massachusetts General Hospital in Boston, USA, said they were “surprised” that RDW “is strongly correlated with patient mortality” in Covid-19 cases.
Dr. Jonathan Carlson of Massachusetts General Hospital, one of the authors of the study published in the journal Jama Network Open, said, “The correlation persisted when other identified risk factors were checked, such as the patient’s age, some other laboratory tests, and some pre-existing diseases. “
The researchers analyzed medical records from 1,641 adults diagnosed with Covid-19 infection and admitted to hospital in the Boston area between March 4 and April 28, 2020.
The team then used various blood tests to look for “complicated changes” in circulating blood cells.
Lead author Dr. John M Higgins, a researcher in the Department of Pathology at Massachusetts General Hospital, said, “We wanted to help find ways to identify high-risk Covid patients as early and as easily as possible – who are likely to become seriously ill and may be from aggressive Interventions benefit and which patients in the hospital are likely to get worse the fastest. “
The researchers found that those with RDW values above the normal range were almost three times more likely to die after being infected with coronavirus compared to Covid-19 hospitalized patients with normal RDW values.
A later increase in RDW after hospitalization is associated with an even higher risk of death, the researchers said.
They add that regular monitoring of the RDW of Covid-19 patients could help determine if they are responding to treatment or if they are getting worse.
As part of the next steps, the team is now trying to understand the biological mechanisms that lead to RDW increases in severe Covid-19 cases.
Dr. Aaron Aguirre, cardiologist and intensive care physician at Massachusetts General Hospital, said, “Such discoveries could indicate new treatment strategies or identify better markers of disease severity.”