3. What is Blood
A blood bank is a center where
blood gathered as a result of blood
donation is stored as preserved for
later use in blood transfusion. The
term ‘Blood Bank’ typically refers
to division of a hospital where the
storage of blood products occurs
and where proper testing is
A blood group also called a Blood Type
Classification of blood is based on the presence or absence of
inherited antigenic substances on the surface of red blood
The ABO blood group system is the most important blood
type system (or blood group system) in human blood
Based on the presence or absence of antigen A and antigen B,
blood is divided into four groups: ‘A, B, AB and ‘O’ group.
Blood having antigen A belongs to ‘A’ group. This blood has β-
antibody in the serum.
Blood with antigen B and α-antibody belongs to ‘B’ group.
If both the antigens are present, blood group is called ‘AB’
group and serum of this group does not contain any antibody.
If both antigens are absent, the blood group is called ‘O’
group and both α and β antibodies are present in the serum.
• Age: 18-60 Years
• Weight: >55 kg
• Hb: > 12g/dL
• If previously donated, at least 4 months should be elapsed since the
date of previous donation.
• Free from any serious disease condition or pregnancy.
• Free from "Risk Factors".
• Drug addicts
• Hepatitis B & C
9. 1. Red Cell Suspension
1. Sample of blood
3. Test tubes 75x12 mm
1. Place 0.2 -0.5 ml of blood into the tube (2-3 drops).
2. Fill the tube with the saline.
3. Centrifuge at 200 G for 1-2 minutes until the RBC's are packed.
(G=relative centrifugal force)
4. Decant the supernatant.
5. Tap the tube to resuspend the RBC's in the residual fluid. This
constitutes one wash. Repeat step 2-5 at least twice. The last wash
should always have a clear supernatant with no signs of haemolysis.
6. To make a 5% cell suspension add 1 volume of the packed RBC's to 19
volumes of saline.
7. To make a 3% suspension, add 1 volume packed RBC's to 32 volumes of
11. Slide Method
Take 3 slides and label them with A, B,
Put 1 drop of Anti-A on the slide
labeled as A, 1 drop of Anti-B on Slide
B, and 1 drop of Anti- D on slide D
Add 1 drop of blood on slide A, 1 drop
on slide B and 1 drop on slide D
Mix the antisera with blood
Check for agglutination.
Prepare 2-5% suspension of test
sample in normal saline
Set three tubes , label them as A,B, D
Add two drops of anti A , anti-B, anti D
in three different tubes
Add one drop of 2-5% cell suspension
(Ratio of 2:1)
Mix contents well and centrifuge at
1500 rpm for 1 minute
Observe for hemolysis
Gently disperse cell button and check
Conform negative results under
• Prepare 2-5% suspension of pooled cells
• Label three tubes A cells, B cells and O cells
• Place two drops of serum in each tube
• Add one drop of cell suspension ( A cell to A
tube, B cell to B tube and one drop of O cell
to O tube)
• Centrifuge tubes at 1500 rpm for 1 minute
• Gently disperse for agglutination.
• Check negative results on microscope.
15. 2 vol of test
Serum / plasma +
1 vol of 5%
reagent red cells in
Shake & leave at room temp (20-24 C) for 5 min
Centrifuge at 1000 rpm for 1 min
Centrifuge & record the results similarly as for cell grouping
16. 3. Weak D
• Principle and Application:
Some red cells possess the D antigen but it is expressed so weakly that the cells are not
agglutinated directly by anti-D sera. An indirect antiglobulin test is necessary to
identify patients with the Weak D (formerly known as Du )phenotype. Weak D testing is
done on all prenatal patients and candidates for Rh immune globulin. Weak D testing is
also done on Rh negative donors to ensure they are truly D negative. It may or may not
be done routinely on Rh negative candidates for transfusion, depending on the policy
of the transfusing institution. If routine weak D testing is done, weak D positive
patients should receive Rh positive blood.
Any sample satisfactory for ABO and Rh testing is acceptable. The weak D is most often
performed directly from the same tube set up for the Rh test, if the patient cells were
a washed 3% suspension.
• Reagents, Equipment, And Supplies
Wash bottle with physiologic saline
Coombs serum - either polyspecific or anti-IgG
Coombs control cells
All reagents, equipment, and supplies used in the Rh TESTING procedure
• Prepare a washed, 3% suspension of patient cells, and set up the D and DC (Rh Control) tubes, if not
already done. (SEE ABO/Rh TYPING PROCEDURE)
• Record the D and DC immediate spin results. If the Rh test is negative, continue with step 3.
• Incubate both tubes at 37oC for 15 to 30 minutes.
• Centrifuge and read for agglutination as usual. If the Rh test is negative, continue with step 5.
• Wash both tubes 3-4 times with saline.
• Immediately after the last wash, add one drop Coombs serum to each tube and centrifuge in the
serofuge the time appropriate for the Coombs spin calibration.
• Immediately resuspend gently and examine for agglutination using the lighted agglutination viewer.
• Record results in the appropriate column on the worksheet
• Confirm all negative results by adding one drop Coombs control cells to all tubes showing no
agglutination and centrifuge 15-30 seconds at high speed in the serofuge.
• Gently resuspend and examine for agglutination. Agglutination should be present in this step or the test
• A negative result in the immediate spin phase but
agglutination in the D tube following incubation
(with no agglutination in the DC tube) indicates a
positive test for weak D. Lack of agglutination is a
negative test and the patient is considered truly D
negative. Agglutination in the DC tube invalidates
• A true weak D should give at least a 2+ positive
result. Weaker results may be due to mixed field
agglutination in an Rh negative individual who
received Rh positive blood, or vice-versa. Obtain a
recent transfusion history on patients who give
inconclusive weak D results.
19. 4. Cross Match
A pre-requisite for blood transfusion
Purpose: to avoid reactions of mismatched
In test tube place 2 drops of recipient’s
Add washed donor red cell suspension
Mix and incubate at 37degree C for 30 mins
Centrifuge at 3000 rpm for 1 minute
Examine for agglutination and hemolysis
◦ Matched - no agglutination and hemolysis
◦ Mismatched - either agglutination or hemolysis