BD complications should be graded for severity and imputability that are also defined by IHN and ISBT. Certain complications of donation are by their nature mild or severe.
- Local reactions - Most local reactions (allergic, hematoma, arm pain syndromes) would not be considered severe, though nerve injury may rarely result in long term disability. Severe consequences are classified as separate reaction types: deep venous thrombosis, arteriovenous fistula, and compartment syndrome.
- Systemic reactions - Vasovagal reactions are characterised as those with or without LOC; they may be further sub-characterised by LOC with or without additional symptoms (convulsions, loss of bowel or bladder control and/or duration of ≥60 seconds), and LOC with or without injury.
- Complications that are by their nature severe include generalised allergic (anaphylactic) reactions, and all major cardiovascular events.
Numerous international studies on BD complications have been published. Unfortunately, definitions of the complications are not comparable and mild and delayed complications are likely to be underreported. Surveys from the USA, Japan and Europe reported incidence rates from 0.8 to 3.5%. Several studies reported reduced return following donor reactions (31-34). Although the bulk of donor haemovigilance literature addresses immediate adverse events, little data exists describing long-term morbidity of such complications. Among long-term complications of blood donation, studies have focused primarily on iron balance.