Blood Banking (MLBB 201)
Changes that occur in Stored Blood
Prof. Dr. Nadia Aly Sadek
Prof. in Haematology and
Director of Blood Bank Centre,
Medical Research Inst, University of Alexandria
Outcomes
 By the end of this lecture, the students will be able to:
 Know the changes that occur in blood bags with
storage
 Know what is blood filtration and its types.
Storage Lesion

Long storage times of blood bags may influence the
quality of blood that is transfused. During storage,
the red cells undergo a number of physical and
chemical changes including:
Increased membrane rigidity
Loss of organic phosphates
Release of pro-inflammatory cytokines
Some changes take place slowly and some take place
rapidly.
Consequences of transfusing older blood
1- Increased in-hospital mortality
2- Increased rates of sepsis
2- Delayed healing of wounds
3- Tumour recurrence.
Immediately after blood donation, the red cells are
subjected to an acidic, hypotonic, anticoagulant
solution which damages a small proportion of them
irreversibly.
Cells that survive the first 24 hours will remain viable for
the end of their life span.
 At least 70% of them remain viable in the recipient’s
circulation 24 hours after transfusion.
 Granulocytes become non-functional after 24 hours,
but still they can cause febrile transfusion reactions.
Some lymphocytes may remain viable for several weeks.
Platelet function declines to zero after 24 hours of
storage.
Biochemical changes
1- Oxygen affinity
Stored blood has depleted levels of 2,3
Diphosphoglycerate (DPG) which causes the oxygen
dissociation curve to shift to the left, so increasing the
oxygen affinity of hemoglobin = less release of oxygen
to the tissues.
2- ATP
There is a time-dependent reduction in intracellular
RBC ATP which is essential for:
- membrane stability
- glucose transport
- oxidative stress defense mechanisms
- membrane phospholipid distribution
The biochemical changes that occur in the stored bags
lead to alteration in corpuscle shape, decreased
deformability, increased aggregability and intracellular
viscosity as well as changes in osmotic fragility.
Immunologic changes
RBcs transfusion produces a state of
immunosuppression in the recipients which
predisposes them to acquire infections or develop
transfusion-related acute lung injury.
Electrolytes
1- Potassium:

During storage, there is constant leak of potassium
out of the cells and levels may sometimes exceed
30mmol/L. After transfusion, potassium rapidly enters
the red cells as they begin active metabolism.
 But it may become a problem with rapid transfusion of
large amounts of stored blood especially in severe
renal failure or in neonatal exchange transfusion.
2- Calcium
 Each unit of blood contains 3g. Citrate which binds
ionized calcium. The liver is able to metabolize 3g of
citrate every 5 minutes.
 In patients with impaired liver function, there is a risk
of citrate toxicity and hypocalcemia. It does not affect
coagulation but patients may have transient tetany
and hypotension.
Acid-Base balance
 During storage, there is gradual accumulation of lactic
acid with a resultant fall in pH, but it is rapidly
metabolized and the citrate by the recipient to
bicarbonate which may then produce metabolic
alkalosis.
Coagulation
Labile coagulation factors i.e. FV and FVIII have a 50%
decrease in activity within the first 72 hours of storage,
but the other coagulation factors remain normal.
Blood filtration
 = Leucoreduction of blood components which is a
process by which leucocytes are removed from blood
by specific WBC reduction filters. There are two types:
1- Pre-storage filtration
2- Bedside filtration.
Pre-storage filtration
Each unit of whole blood is filtered before storage. Prestorage filtration has many advantages:1- Diminished accumulation of leucocyte-derived
cytokines during storage.
2- Removal of cells infected with cytomegalovirus
(CMV) and Epstein-Bar virus (EBV) and HTLV-1 virus.
3- It decreases recurrent transfusion febrile reactions.
4- Improves RBCs potency
5- Reduces HLA alloimmunization
Disadvantage:It may activate the complement system.
Bedside filtration
It is carried at the beside of the patient with a different
type of filter.
Although it removes the remaining leucocytes yet it does
not remove the cytokines already secreted from the
leucocytes and which are responsible for the
transfusion reactions.
Study questions
 State true or false:
a- Bedside filtration is better than prestorage filtration
b- Tetany is a sign of hypocalcemia
c- Potassium decreases in blood bags by prolonged
storage
d- RC membrane rigidity decreases by storage.
Assignments
 Stem cell transplantation
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