Why is the cut off age for bone marrow donors so much lower that the cut off age for blood donors?

Bone marrow donation is a much more serious procedure than simple blood donation, involving drilling into a bone and extracting marrow. It is a bit riskier and also because it is tissue donation it is harder to "clean" from possible medications, viruses, etc. so if you are an older person it is more likely you have stuff in your body that we don't want to put into a recipient's body.

ok, both the previous answers are wrong so here is the REAL answer.

You don't just donate bone marrow. You are tissue typed and placed on a list. When someone needs a transplant they search the database looking for a match. The odds of you being a perfect match to someone are very small. Almost 1 in a million.

Its estimated that you need to be on the register for over 10 years just to have a 1 in 1000 chance of matching one person.

Tissue typing is not cheap. It costs about £200 per person. This means that if you could not be on the register for a good amount of years it is highly unlikely you will match and it would not be worthwhile.

EDIT** also for the record we don't normally DRILL marrow out anymore. Over 90% of donations are peripheral stem cell collections. This is a bit like donating blood but takes 2-3 hours instead of 20 mins. There is no surgery, no anaesthetic and very little risk to the donor. REALLY p*sses me off when people are misinformed about the process as it puts off potential donors.

I'm not sure but here are my theories:

1. bone marrow can be rejected alot easier than blood.

Even if there is a slight mismatch.

If someone has to have a bone marrow tranfusion, the donor is mostly somebody from the close family members (siblings parents). Stranger bone marrow is rarely accepted.

For that reason, i guess if you dont have alot of choice, you are compelled to use a family members matching bone marrow. even if they are really young.

2. Bone marrow isnt taken in the amount required from the donor. A little quantity of it is taken and then it is cultured and grown. So, that small amount withdrawn from the young donor doesnt affect the donors health as much. Whereas the same is not with blood, right?

EDIT: oh ****. all my theories proved wrong :O

wow how really nice of you <3