Why transfused blood has lower 2,3 - BPG levels

Question

I read the following quote in the textbook Kaplan Biochemistry (2018 edition, page 183):

Transfused blood has lower than expected 2,3 BPG levels, making it less efficient at delivering oxygen to peripheral tissues.

If I think about this, the answer must lie in glycolysis.

Normally if we had collected blood we collect it in fluoride bulb for glucose estimation. However. in transfusion bag we have CPD-A (citrate, phosphate, dextrose, anticoagulant) but none of it would inhibitors of glycolysis,

Why transfused blood has lower 2,3 - BPG levels? Is storing in cold temperatures of transfused blood slows down glycolysis?

Answer 1

Simpler than you think, its all about the high affinity of 2,3 BPG in binding to the deoxy-haemoglobin site. Now, when you deliver blood infusion into a closed circulatory system, you lower the 2,3BPG levels so that glycolysis in erythrocytes is shifted (by La Chatelie) to make more 2,3BPG. The total result is high 2,3PBG concentration(for a stable volume of blood) which means you got more 2,3BPG that is competing with haemoglobin on the oxygen binding site. The conclusion is poor oxygen delivery to the tissues. Keep notice that youll get more "T" haemoglobin, its like you took the poor patient and putted him on the height of Mt. Everest.

Btw, citrate is a weak calcium binder(agonist of blood clotting) - so technically he can serve as anticaog. (but because the infusiones kept in low temp. there equillibrium is ideal not to ruin the coag. properties by citrate and etc.)