R.H Typing, Along with determining the A.B.0 group, the RH of the blood is also done. Generally, people have positive blood groups and very few people have a negative type in the world.
Test Tube Method:
- Add three drops of blood to ten milliliters of normal saline to make a 2-3% solution.
- Wash the blood twice separately with coconut saline and then make a 3% RBC solution.
- Place 2 drops of 3% solution in a tube and add one drop of known Anti-D.
- Centrifuge the tube at 3400 RPM for half a minute by gently shaking the tube.
- If bubbles are seen in the tube or the reddish solution is united and the cells are not visible separately, then the RH type will be positive, otherwise negative.
In this method, RH Type can be determined by placing drops on a slide instead of a test tube.
- Place one drop of direct blood or Augelite blood on the slide.
- Now put one drop of known (RH (D) on the blood i.e. put one drop of Anti-D on the blood.
- Now mix it well with a glass rod or wooden stick.
- After 2 minutes if small blisters are seen then (RH Type) will be positive and if no small blisters are seen and the blood is homogenous then (RH Type) will be negative.
If the tube method shows no clots, test the blood for DU.
- Place the test tube at 37 degrees for 30 minutes.
- Then wash 3 times with normal saline.
- Now add two drops of ant globin (Coombs) serum to the tube and spin it at RPM 3400 for ten seconds.
- Now if three spots appear in the tube then DU will be positive. This is called the DU variant of blood.