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8. Hyperkalemia.

9. Citrate toxicity.

10. Clotting abnormalities (after massive transfusion).

Complications Appearing Late

1. Disease transmission, e.g.

• Hepatitis B/C

• Syphilis

• Malaria

• Cytomegalovirus

• AIDS.

2. Transfusional iron-overload.

3. Immune sensitization.

Investigations in a Case of Transfusion Reaction

The occurrence of a transfusion reaction should be

immediately reported to the blood supplying laboratory or

bank.

The reporting authority should send:

1. A post-transfusion blood sample.

2. A post-transfusion urine sample.

3. A pre-transfusion blood sample.

4. If the blood has been discontinued, the bottle and the

tubing intact should also be sent.

The Laboratory or the Bank Providing the Blood should

Already have

1. The patient’s original cross-match specimen (these

should be preserved for at least 48 hours after

dispatching the blood or its products).

2. The donor’s pilot tube/bottle (also to be preserved for

48 hours as mentioned above).

3. All the laboratory/bank records.

Proceed as Mentioned Below

1. Inspect the post-transfusion urine sample for the

presence of hemolysis—hemoglobinuria. Centri -

fuge the specimen to see if the red color stays in the

supernatant (hemoglobinuria) or goes down with the

sediment (hematuria).

372 Concise Book of Medical Laboratory Technology: Methods and Interpretations 2. Centrifuge the post-transfusion blood specimen.

Inspect the serum for the presence of hemolysis.

If hemolysis has been established report it to the

concerned physician/surgeon so that he may treat the

patient as a case of hemolytic transfusion reaction.

 To Establish the Cause of Hemolysis:

3. Regroup and retype the original donor pilot blood

sample, the original patient’s cross-match sample, the

blood in the blood bottle or tubing.

4. Group and type the new patient’s pretransfusion blood

sample (if available—and post-transfusion specimen).

5. Recross-match—if available use combined saline and

Coombs’ cross-matches—the donor blood with the

original patient specimen.

6. Cross-match the donor blood with the new patient

specimen.

7. Make hanging drop preparation and Gram stain of

blood in tubing or blood bottle looking for bacteria.

Culture the blood in the bottle or tubing.

8. Schumm’s test—a spectroscopic examination of plasma

for the bands which are typical of methemalbumin—

found when there has been intravascular hemolysis.

Interpretation of Results

1. If there was no evidence of hemolysis in the blood

and no free hemoglobin in the urine, the patient has

not had a hemolytic reaction, but a pyrogenic/allergic

reaction.

2. If there is evidence of hemolysis in the blood and

hemolysis in the urine (hemoglobinuria), a hemolytic

transfusion reaction has occurred.

3. If the recross-matching shows incompatibility, then

the first cross-match was done or recorded in error.

4. If the recross-match with the original patient specimen

is compatible, but the cross-match with the new

patient specimen is incompatible, the mistake lies in

mistaken identification of the patient, either when the

first sample for cross-match was done, or at the time

of giving the transfusion.

5. If the saline cross-matches are compatible but the

Coombs’ cross-matches are incompatible then the

problem lies with an immune antibody incompatibility—the most common being the Rh incompatibility.

Laboratory Diagnosis of Hemolytic

Disease of the Newborn

Laboratory findings at birth:

1. Cord blood:

• Variable anemia (Hb < 18 g%)

• Reticulocytosis

• Hyperbilirubinemia

• Positive direct Coombs’ test

• Baby is Rh positive.

2. The mother:

• Is Rh negative, and

• Has a high plasma titer of anti-D.

TROUBLE SHOOTING

General Instructions for Blood Grouping

Sample Preparation

¾ Depending upon whether serum or plasma is to be

used as sample for testing, blood may be collected with

or without an anticoagulant.

Serum versus Plasma

For blood grouping tests, serum is preferred to plasma

for the following reasons:

1. Plasma samples may clot when incubated at 37°C.

2. The detection of some antibodies depends upon

complement activation and anticoagulants such as

citrate of EDTA prevent complement activation by

chelating calcium.

¾ Containers for blood collection and processing should

be clean and dry, free of detergents; acids and alkalies,

ideally made of plastic or siliconized glass tubes.

Sample Processing

¾ Need to wash red cells (Tube test)

Red cell suspension used in blood grouping should be

washed free of their own plasma. If this is not done clots

will form when the red cell suspension, which contains

fibrinogen, is mixed with serum, which contains

residual thrombin.

Other reasons for washing red cells are as follows:

1. Plasma tends to cause rouleaux formation, which

interferes with the interpretation of agglutination

tests.

 Rouleaux or pseudoagglutination is a phenomenon

characterized by a person’s serum causing his own

and other red cells to line up in formations which

resemble stacks of coins. This is easily mistaken for

true agglutination.

 Causes of rouleaux:

a. Concentration of serum.

b. Increase of plasma proteins.

c. The transfusion of macromolecular medium, e.g.

dextran.

d. Inverted albumin/globulin ration as in chronic

nephritis, Kala-azar, and multiple myeloma.

e. Infections with an increased red cell sedimentation rate.

Blood Banking (Immunohematology) 373

2. Plasma contains anticoagulants, which are anticomplementary and may thus interfere with the

detection of complement binding antibodies.

3. Preservative substances added to red cell suspension,

e.g. lactose or neomycin, are occasionally responsible for agglutination due to the presence of

a corresponding antibody in the patient’s plasma;

most of the antibodies concerned do not react with

red cells washed in saline.

4. Plasma contains blood group substances corresponding to those on the red cells and these substances

may inhibit the antibody in the test serum.

5. Plasma may contain so-called albumin autoagglutinins and may then cause false-positive reactions

when whole blood is added to a serum-albumin

mixture.

Sample Storage

¾ Effect of storage on red cell antigens

1. Red cells stored as clotted blood lose their antigenic

activity more rapidly than when stored with citrate

anticoagulant.

2. Similarly, when blood is collected into plastic bags,

if the donor line is not emptied immediately after

collection and then refilled with blood mixed with

anticoagulant, the clotted blood in tubing is an

unreliable source of red cells for cross matching tests

3. Red cells stored as clotted blood may give falsepositive reactions in the antiglobulin test due to

uptake of complement components during storage

at 4°C.