STANDARD OPERATING PROCEDURE (SOP):PREPARATION OF RED CELL SUSPENSION

BLOOD CENTRE NAME

1.SCOPE AND APPLICATION

This procedure applies to all testing that requires red cell suspension preparation.

2. RESPONSIBILITY

It is the responsibility of every technician performing a given test to prepare the appropriate red cell suspension.  Every morning, the shift duty technician must prepare A, B & O red cell suspension for the day’s use.

3. REFERENCES

• Technical Manual of American Association of Blood Bank, 18^THEdition, 2014, Pages 149, 311, Method 1-7.
• Model Standard Operating Procedures for Blood Transfusion Service, WHO, New Delhi 2002.  

4. MATERIALS REQUIRED

    EQUIPMENT: Calibrated centrifuge

    REAGENTS: 0.9% normal saline.

           SPECIMENS:

• Clotted or anticoagulated blood specimen of donor. 
• Clotted or anticoagulated blood specimen of patient.
• Donor unit segment.

            GLASSWARE:

• Pasteur pipettes. 
• Serum tubes.

             MISCELLANEOUS:

• Discard box. 
• Plastic beakers. 
• Rack to hold tubes.

5. PROCEDURE

    PRINCIPLE:

The ratio of serum to red cells may dramatically affect the sensitivity of agglutination tests. Consistent preparation of either 2 to 5% red cell suspension is critical to any agglutination test.

   POOLED CELL SUSPENSION:

1. Label tubes with pooled A, B, and O groups and 5% A, B and O group
2. Place one drop of red cells each from 3 blood bag’s segment containing A group into the A labelled tube. 
3. Place one drop of red cells each from 3 blood bag’s segment containing B group into the B labelled tube 
4. Place one drop of red cells each from 3 blood bag’s segment containing O group into the O labelled tube 
5. Fill the tube up to ¾ full tube with 0.9% saline to resuspend the cells. 
6. Centrifuge the tubes for 3 minutes on 3000rpm speed. Decant the supernatant fluid. 
7. Repeat steps 5 and 6 for 3 times to give properly washed cells.
8. Remove any debris or fibrin with the pipette. 
9. Test the pooled cells prepared using the antisera (anti-A, B, AB and D) in use.
10. For making 5% red cell suspension, add 1 drop of washed red cell to 19 drops of saline marked 5% tube of each blood groups
11. Mix the tubes gently. 
12. The cells should be kept at 4 ± 2⁰C in the refrigerator when not in use.

 6. LIMITATIONS:

Hemolysis of the red blood cells from improper washing may result in false results. A cell suspension that is too heavy or too light may produce false positive or false negative results.

 7. DOCUMENTATION

• Enter the donor unit numbers from which pooled cells are prepared in the donor register. 
• Record the results of testing with the antisera in use. 
• Enter the manufacturer’s name and batch number of the antisera.

  8. END OF DOCUMENT