CLINICAL LAB SCIENEC

CHAPTER 17: IMMUNOHEMATOLOGY (BLOOD BANKING) 423
The procedure below describes the tube method. In this procedure, the test is
for the presence of antigens A and B that may be found on the surfaces of RBCs,
depending upon the ABO grouping of the cells.
Equipment and Supplies
1. Gloves, disposable paper towels, and disinfectant or other cleaning solution
2. Report form
3. A 2% to 5% RBC suspension of washed RBCs from the patient being tested, prepared
following the steps set out in Procedure #1
4. Waterproof sharp marker
5. Normal physiological (0.85%) saline (blood bank quality) in squeeze bottle
6. Disposable Pasteur pipettes or transfer pipettes
7. Anti-A blood serum
8. Anti-B blood serum
9. Commercially prepared Group A cells (2 – 5% cell suspension)
10. Commercially prepared Group B cells (2 – 5% cell suspension)
11. Disposable 12 × 75 mm test tubes and test tube rack
12. Centrifuge (serofuge) with head that will contain 12 × 75 mm tubes at 2000 rpm
13. Illuminating lamp with magnifying mirror (optional)
14. Disposal containers appropriate for biohazardous waste and sharps container
Procedure
1. Wash hands and don gloves.
2. Assemble necessary equipment and supplies.
3. Prepare a 2% to 5% RBC suspension of washed RBCs from the patient being
tested following the steps set out in Procedure #1.
4. Label one 12 × 75 mm tubes “A” and label one “B.”
5. Using a Pasteur pipette or transfer pipette, place two drops of the suspension in
each tube.
6. Into tube A, put two drops of antisera A, which is prepared from serum from a
group B individual.
7. Into tube B, put two drops of antisera B, which is prepared from serum from a
group A individual.
8. Tap or gently flick each tube with a finger to mix the cells and antisera.
9. Place both tubes into a centrifuge (called a serofuge in blood banking), and spin
for 30 seconds.
10. Gently remove the tubes without shaking and slightly tilt the tubes while observing
for clumping, called agglutination. An illuminating lamp with magnifying mirror
may be used as an optional practice.
11. Record which tube or tubes show agglutination, using the following form. Place
a plus sign (“+”) for agglutination into the appropriate blank(s) and a minus sign
(“–“) to indicate no agglutination.
Results
Tube A
Tube B
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