Intern Medical Lab Scientist

Blood transfusion reactions refers to the recipients’

response in receiving donors’ blood/ blood product.

If transfusion is necessary then ensure

Right blood/ blood product

Right time

Right place

Right patient

Red blood cells compatibility

ABO incompatible red cell transfusion is often fatal and its prevention is the most important in clinical practices.

ABO antigens are always on surface of the red cells and sometimes on platelets and other tissues.

Alloantibody are produced whenever an individual is exposed to different group by transfusion or pregnancy.

RH antibodies are not natural occuring.

In case a recipient is transfused with incompatible red blood cells anti- A or Anti-B in the recipients’ blood activates the complement pathway leading to destruction of transfused cells ( intravascular hemolysis).

Plasma compatibility

Transfusion of ABO incompatible plasma containing anti-A or anti-B causes hemolysis of recipients’ blood cells especially from group O donor.

Group O rich components should not be given to patients of group A, B or AB.

Platelets and cryoprecipitate incompatibility

do have reactions too but so far less cases are reported.

Immune mediated –Immune mediated transfusion reactions occur when incompatible blood products trigger a response from the patients’ immune system.

Non-immune mediated-These reactions are not attributable to the immune, it could be mechanical error, volume overload etc

They occur in 24 hours of transfusion, often occur in initial hours of transfusion, it involves intravascular hemolysis or extravascular hemolysis

Intravascular hemolysis

It occurs mostly inside the blood vessels

It involves the complement pathway

Massive activation of the compliment pathway

Extravascular haemolysis

In this donors RBCs are removed from circulation by macrophages present in the liver and spleen.

Its more slower and more controlled thus effects can only be fever and chills and it seldom results to jaundice as liver controls it.

Occurs in 1 day or maximum 2 weeks after transfusion

The antibodies are not easily detected in the standard cross match done in our routines, likewise in transfusion time

The recipients antibodies are of previous sensitization

Fever without any signs of hemolysis.

Patients preformed antibodies attacks transfused WBCs.

Most common in multitransfused and multiparouspatients.

Thrombocytopenia occurring in 5 to 10 days after transfusion.

Purpura is purplish discoloration of the skin.

PTP is more common in women because pregnancy increases the likelihood of forming platelet forming antibodies.

Often happens to patients who have a history of hay fever.

An existing IgE antibody triggers the release of histamine from patients mast cells and basophils.

Symptoms are usually mild and can be controlled by giving antihistamines.

It’s a life threatening allergic reaction.

Its accompanied with difficulty breathing and wheezing.

There might also be nausea and vomiting, respiratory arrest or circulatory shock in absence of fever.

Its rare and often fatal characterized by sudden shortness of breath.

Donor antibodies attack recipients WBCs and tend to aggregate in the vessels that supply the lungs.

WBCs in the lungs release inflammatory mediators that tend to cause permeability in the lungs causing a lot of fluid accumulation.

The result is pulmonary edema.

Transfused blood cells (graft) attacks patients’ (host) cells.

Mostly occurs when recipients’ are immuno-compromised who can not eliminate the cells.

Surviving donor T cells attack the cells that bear HLA antigen.

Patients like this are given irradiated blood products.

The end result is often grave in few weeks if its encountered.

Its often a result of mechanical errors often to pts who receive multiple transfusions.

It can be blood that is not warmed before transfusion resulting to hypothermia.

Can also be volume too big to handle.

Old RBCs transfused can release potassium causing risk of arrhythmias.

Finally infectious material in donors blood. Could be bacterial or viral after donor donates blood.

A lab has to be equipped with ALL vital reagents for pre transfusion tests e.g. Coombs reagents.

It should provide job aids for all processes.

Regrouping of blood is necessary if possible.

Ensuring storage condition of each product is in accordance.

If possible a titre of immunoglobulin in each bag should be known.

Ensure all patients identity details are in written and the clinical history should match reason for transfusion.

A patient received 5 units of fresh frozen plasma (FFP) and developed a severe anaphylactic reaction. He has a history of respiratory and gastrointestinal infections. Post-transfusion studies showed all 5 units to be ABO-compatible. What immunologic test would help to determine the cause of this transfusion reaction?

A) Complement levels, particularly C3 and C4B) Flow cytometry for T-cell countsC) Measurement of immunoglobulinsD) NBT test for phagocytic function

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