Any questionsBMJ 1997; 314 doi: https://doi.org/10.1136/bmj.314.7084.0g (Published 22 March 1997) Cite this as: BMJ 1997;314:g
The UK Guidelines for the Blood Transfusion Service state that an absolute minimum interval of 12 weeks should be left between donations of whole blood, while also stating that “usually” only two donations should be given in a 12 month period. The risk to the donor of frequent donation is that of iron deficiency, and clearly it is impossible to define a minimum interval that will be equally appropriate to all donors (some other countries bleed donors as frequently as every eight weeks, sometimes with the help of iron supplements). It is also important to take into account the level of haemoglobins considered necessary for blood donation (currently 135 g/l for men and 125 g/l for women) are recommended in the United Kingdom. The arguments have been well rehearsed, and the current United Kingdom recommendations are produced for the United Kingdom transfusion services by the standing advisory committee on donor medical care and selection policies.
Blood donors are usually advised not to undertake in the 24 hours or so after donation any activity which might put them at risk if they should faint.1 Such so called delayed faints are relatively uncommon, but are quite unpredictable and occur even in experienced regular donors. A full whole blood donation amounts to 10-13% of total blood volume, depending on body weight, a volume loss which should not be regarded as trivial.
My understanding of the use of a plaster to cover the site of venepuncture is that it might help prevent bleeding. I am not aware of any evidence that it could also prevent infection, but full marks to the donor attendant for coming up with an explanation that was at least plausible.