BLOOD TRANSFUSION REACTIONS AND INVESTIGATION OF SUSPECTED

BLOOD TRANSFUSION REACTIONS AND INVESTIGATION OF SUSPECTED

TRANSFUSION REACTIONS:-The term transfusion reaction means an obviously adverse response to transfusion, usually during, or immediately after, the transfusion. The transfusion reactions can be of four main types: haemolytic, febrile, allergic or those due to circulatory overload. However, poor survival of the transfused blood, or failure to achieve the desired clinical effect in the patient, should also be considered as mild forms of transfusion reactions.

Haemolytic Transfusion Reactions:- The true haemolytic transfusion reaction is caused by the in vivo combination of an antibody with red cells possessing the corresponding antigen. In most severe reactions, the antibody is in the recipient's plasma and the antigen on the donor's red cells (major incompatibility).

Minor incompatibility occurs when the antibody is in the donor's plasma and the antigen on the recipient's red cells. Antibodies which are readily haemolytic in vitro are most likely to cause haemolytic transfusion reactions e.g. complement binding IgM type of antibodies. Anti-A and anti-B antibodies is the major cause of this type of reactions, and the incompatible red cells are lysed intravascularly within a few minutes.

Antibodies which are not haemolytic in vitro such as IgG antibodies to Rh-antigens usually cause extravascular instead of intravascular haemolysis. Antibodies of this type usually coat the red cells resulting in their removal from circulation by the spleen. This results in raised bilirubin levels in the serum, and may be associated with haemoglobinaemia and haemoglobinuria. Most antibodies other than anti-A and anti-B produce this type of transfusion reactions.

Delayed haemolytic transfusion reactions may be seen in patients who are already immunised to certain blood group antigens. Anti-E or anti-c Rh antibodies, and antibodies of the Kidd system are likely to cause such delayed type of haemolytic reactions.

Febrile Transfusion Reactions:- Febrile reactions are manifested as chills and varying degrees of fever. The almost universal use of disposable blood containers and tubing has eliminated those febrile reactions due to pyrogenic products of bacterial growth. Many febrile reactions are caused by the recipient antibodies directed against donor leukocyte antigens, or due to some plasma proteins.

Allergic Transfusion Reactions:- Allergic reactions usually appear as urticaria appearing during the transfusion. The skin lesions are pale, irregular, slightly raised patches. More serious reactions may result in facial or glottal oedema or asthma, or pulmonary oedema. Such allergic reactions may be caused by passive transfer of donor allergens to the recipient.

Transfusion Reactions Due to Circulatory Overload :- Patients who already have increased plasma volumes or incipient heart failure, may feel tightness in the chest and dry cough after transfusion of whole blood. It may also lead to pulmonary oedema.

Other Causes of Transfusion Reactions :- These include various forms of embolism (e.g. air embolism), transfusion of ice-cold blood, contaminated blood components, citrate toxicity and graftversus-host disease (GVHD).

Common forms of transfusion reactions are summarised in Table

INVESTIGATION OF SUSPECTED

TRANSFUSION REACTION:- A standardised investigational procedure should be used for all suspected transfusion reactions. The most important immediate step is to check the clerical records that the patient has received the blood intended for him. A laboratory.

Schedule for investigations of transfusion reactions

A. All reported reactions

 1. Specimens needed

(a) Pretransfusion blood of recipient

(b) Posttransfusion blood of recipient 

2. Investigation (letters refer to specimens listed above)Check donor and patient identification and crossmatch report Repeat ABO and Rh typing (b and donor bag, if indicated) Direct antiglobulin test (b, if indicated) Examine for visible hemolysis (b): if necessary, compare (b) with (a) If these procedures reveal no evidence of incompatibility or haemolysis, and there is no additional information to arouse suspicion, no further investigation is needed. Otherwise, proceed as follows:B. If there is evidence of haemolysis or incompatible transfusion

1. Specimen needed

(a) Pre-transfusion blood of recipient

(b) Post-transfusion blood of recipient

(c) Pilot samples of donor blood

(d) Blood from container implicated in reaction (if available)

(e) Post-transfusion urine 

2. Immunological investigation

2.Repeat ABO, Rh and direct antiglobulin test (a.c,d) Repeat crossmatch (a, b, c, d if indicated) (major, minor only if indicated) Repeat antibody screen (a,b,c) (special, sensitive techniques if necessary)Identification of any unexpected antibody or incompatibility 

3. Other procedures as indicated Serum haptoglobin (a,b) Bacteriological smear and culture (d) Serum urea and bilirubin (a,b) Urine haemoglobin (e)Urine haemosiderin (e) 

4. Investigation of nonimmune causes of haemolysis