Blood test ‘could help predict which Covid-19 patients are at higher risk of dying’

The red cell distribution width test measures the range in the volume and size of red blood cells (Simon Dawson/PA)

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 width (RDW) test, it measures the range in the volume and size of red blood cells.