Weight

1. Bone Marrow Donor:
Must not donate if:
a) Body Mass Index over 35.

b) Under 50 kg (7 stone 12 lb).

2. PBSC Donor:
Must not donate if:
a) Body Mass Index over 40.

b) Under 50 kg (7 stone 12 lb).

c) The donor is so overweight that they have difficulty in getting onto or off the bleed bed.

d) Venous access is very difficult.

1. Bone Marrow Donor:
a) If the Body Mass Index >35 to <40: Refer to DCSO. Obtain anaesthetic option, considering other anaesthetic risk factors and technical feasability.

2. PBSC Donor:
a) If Body Mass Index 40 – <43: Refer to DCSO, considering venous access.

b) Treatment with anti-obesity drugs, accept.

Blood service staff should not put their own health at risk by helping donors on and off the donation couch except in an emergency.

It is recommended that no donor should lose more than 13% of their blood volume during any donation procedure. This is to protect them from adverse effects such as fainting and becoming anaemic.

Obesity also makes it desirable to use more than a donor's weight to estimate their blood volume. Fat contains far less blood as a proportion of its weight than muscle. In obese individuals the blood volume can be seriously overestimated from weight alone. Overestimating a donor's blood volume makes it more likely that they will have an adverse incident.

Donors who are overweight or obese tend to have more moderate-severe pain with PBSC donation. BM harvest is technically a considerably more difficult procedure in overweight donors. There is much evidence to support the concept that the morbidly obese in general (i.e. with a BMI >35) have a higher risk of premature death, anesthetic complications and occult cardiovascular disease.

However, it is recognised that a high BMI does not always reflect obesity and body habitus and many high BMI donors may be fit and suitable to donate.

The levels of BMI/weight at which a BM or PBSC donor can be accepted have been changed to align with WMDA guidance.