Hello everyone,how are you all? I hope you all are doing well and i am too. Today we are going to see the blood bags and their composition and what are their uses. As blood can't be created artificially, blood needs to be donated. Many people donate blood because to save lives of others.After donating the blood, where it is collected, stored and what are components we cam make from it we will see.

The patient's whole blood is collected in a plastic bag and the volume of bag is 350 ml or 450ml.
Median cubital vein is selected and tourniquet is tied and blood is collected into a 350 ml or 450 ml blood bag which contains CPDA or CPD. Here you can see blood is collected in bag which contains CPD and some bags.

Date of collection and time is mentioned on the bag because every blood bag has expiry date and it should be discarded after it crosses that shelf life time. You can also see serology tests is labelled with syphilis, HBV, HCV, HIV I and II, Malarial parasite labelled. This is because we have to screen all these infectious agents before transfusing it.

C- Citrate - Anticoagulant (blood won't get clotted)
P- Phosphate - acts as Buffer and maintains pH
D- Dextrose - Substrate for energy
A- Adenine - ATP generation
Some bags may or may not contain A(Adenine)

Shelf life for PRBC if it has CPD - 21 days
Shelf life for PRBC(packed red blood cells) if it has CPDA-1 - 35 days
Storage - at 2-6 degree celsius

SAGM
S- Saline - Suspending solution
A- Adenine - for ATP generation
G- Glucose - Substrate for energy
M- Mannitol - Red cell membrane stabilizer

Shelf life for PRBC (Packed Red blood cells) -

Transfer bag for buffy coat -
So after centrifugation or soft spin then the PRBC settle down but the Buffy coat will remain on top of PRBC because of its low specific gravity compared to red blood cells and the buffy coat contains white blood cells and platelets and plasma will be more on the top.
Buffy coat is used to prepare Random Donor Platelets (RDP)
This is a transfer bag which is 100ml and we will transfer SAGM to this bag also.

Transfer bag - for the storage of plasma at -30 degree celsius which is 350 ml
This bag is used for making fresh frozen plasma

So selection of blood bag depends on what components we are making and number of platelets to be prepared on the day etc..... There are single bag, double bag, triple bag, quadruple bag, quintuple bag.

The above image shows quadruple bag and it is most commonly using here so i shared here.
i will come up with how the components of blood will be separated in the next posts.

References -

• Kawthalkar SM. Essentials of Clinical Pathology. 2nd edition 2018.
• TRANSFUSION MEDICINE TECHNICAL MANUAL Third Edition 2023

Thanks for reading,
with regards,