In an emergency, therefore, it is possible to use

blood which is minor incompatible (but major compatible) without leading to transfusion reaction. Sometimes

however, one can get into difficulty by transfusing blood

which shows a minor incompatibility as given below.

High titer of donor antibodies: If the titer (amount)

of antibodies in the donor blood is very high, then even

if there is dilution of the donor’s plasma in the patient’s

plasma, the antibodies may still be present in significant

numbers to cause agglutination, hemolysis and result in a

reaction. O donors with high titer are said to be dangerous

universal donors.

Method of Cross-matching Universal Donor Blood

1. Do major cross-match as described (Fig. 11.7).

2. Make a 1:100 dilution of donor serum in saline.

3. Use this diluted serum for a minor cross-match.

4. If there is no agglutination on minor side using the

1:100 diluted serum, then this a low titer (< 1:100)

plasma and can safely be transfused as long as too

many bottles of such blood are not needed.

5. If there is agglutination on the minor side, it means that

this is high titer (> 1:100) plasma and should better not

be used especially if more than one unit is required (for

AB patient, it is possible to use A, B, or O donor blood.

Whichever is given, it should be cross matched in this

way).

Factors Leading to False Results

1. Auto-agglutination

2. Cold antibodies

3. Bacterial contamination

4. Drying.

If Still an Unexpected Incompatibility is Obtained

1. Test for autoagglutination.

370 Concise Book of Medical Laboratory Technology: Methods and Interpretations 2. Test for cold antibodies.

3. Regroup the patient and donor cells.

4. Back-type (serum type) the patient and donor serum.

5. Repeat the cross-match by tube technique.

6. Check the records to see if patient’s present grouping

is correct.

7. Ask for a fresh patient specimen, if necessary.

Choice of Material for Transfusion

1. Shock due to hemorrhage or decreased blood volume:

Whole blood fresh, stored or preserved.

2. Shock resulting from trauma, burns, or infection:

Plasma liquid, frozen or dried; plasma substitutes.

3. Chronic anemia: Whole blood or resuspended red

blood cells.

4. Leukopenia: Large amounts of fresh whole blood.

Leukocyte concentrates.

5. Prothrombin factor deficiency not corrected by

vitamin K: Fresh whole blood.

6. Hemophilia: Factor VIII (AHF) cryoprecipitate

concentrate. Factor IX complex concentrate. Whole

blood or plasma administered within 6 hours of

collection.

7. Thrombocytopenia: Platelet transfusion with fresh

(< 3 days old) platelets.

Blood and its Products

Whole blood: In most instances whole blood is

requisitioned by the concerned physician/surgeon, except

in certain circumstances when a special preparation may

be asked for.

Fresh Blood

Stored bank blood contains nearly all of the substances

required in a usual transfusion therapy. A few labile

substances are lost.

1. Platelets: These stick to the rubber and glass surfaces

and also die soon or become non-functional. If

platelets are needed, fresh blood is necessary.

2. WBC’s: These die fairly rapidly. On occasions, where

the patient is suffering from severe leukopenia with

infection, a transfusion of fresh blood provides viable

leukocytes which help to fight the infection but which

do not raise the WBC count.

3. Factor VIII: Anti-hemophilic globulin. Patients with

hemophilia should be transfused with fresh blood if

they need transfusion to help stop bleeding, since AHG

disappears rapidly from stored blood.

4. Other labile factors: Can be provided by giving frozen

or dried plasma.

Packed Cells

Sedimented cells: The bottle kept in the refrigerator shows

at bottom settled cells and above it the plasma. In chronic

anemia one may want to transfuse just the packed cells.

This can be prepared by aspirating the plasma into a

separate sterile bottle, leaving the cells in original bottle.

FIG. 11.7: Method of cross-matching universal donor blood

Blood Banking (Immunohematology) 371

Label the plasma bottle with the date, the bottle number

and the group and type of the blood from which it is

obtained, aspirate a small amount of plasma into a ‘pilot’

tube for later cross-matches.

The packed cells should be transfused within 4 hours.

Aspirate plasma only when someone comes to collect

it, this ensures that the packed cells would be used

immediately.

Plasma

The ACD plasma aspirated from the sedimented cells may

be stored for months at 4–6°C and is safe for transfusion.

If the plasma becomes cloudy or shows floating granules

(bacterial colonies)__suck little bit of it from the top, do a

hanging drop and Gram stain of the same—discard if it

is found contaminated. Minor cross-matching should be

done with the patient’s red cells and the donor’s plasma.

Plasma may be used as:

1. Liquid plasma: It should contain 5% dextrose to

prevent precipitation of fibrin at room temperature.

The prothrombin titer diminishes rapidly after 72

hours. Liquid plasma may be kept at room temperature

for 3 years. Hepatitis virus is attenuated or destroyed

in plasma that has remained at room temperature for

6 months.

2. Frozen plasma: Plasma frozen within 72 hours after

blood is drawn may be stored indefinitely at –20oC

(–4oF). Reliquefy at 37oC (98.6oF) in a water bath and

use promptly. Frozen plasma retains its full content

of labile constituents (prothrombin, complement,

antibodies). Hepatitis virus is also preserved, frozen

plasma should therefore not be used unless no other

substitute for blood is available.

3. Dried plasma: Plasma dried after freezing within

72 hours after blood is drawn is stable at room

temperature for 5 years if kept in an airtight container.

Reliquefy with 0.1% solution of citric acid and

administer within 1 hour. Dried plasma retains its

full content of labile constituents. Hepatitis virus is

preserved too.

Blood Transfusion Complications

Complications Appearing Early

1. Hemolytic reaction:

• Immediate or

• Delayed.

2. Reactions due to infected blood.

3. Allergic reactions to white cells, platelets or proteins.

4. Pyrogenic reactions (febrile reactions)

• Pyrogens may come from the bottle, tubing,

or the blood itself. Precaution should be taken

that equipment, solutions, etc. used should be

absolutely sterile

• Bacterial contamination too would lead to

pyrogenic reaction.

5. Circulatory overload.

6. Air embolism.

7. Thrombophlebitis.