14098 inactive donors were randomly divided into three groups according to age, sex, blood donation frequency,time of last donation and blood donation site, one group acted as the control group, one will be recruited by telephone recruitment on "need", and one will just be called for improvement suggestions of blood donor service.
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
donate blood or not
Timeframe: 12 months