When someone is badly injured, doctors urgently need two facts: the patient’s blood type, so that a transfusion is safe, and their hematocrit, the share of the blood made up of red blood cells, which reveals blood loss or anemia. Hospitals measure both with large machines that need electricity and trained staff, which are often unavailable in ambulances, disaster zones or remote clinics.
Hand-cranked device tells blood type and red cell levels in 1 minute
