What are the steps in typing blood?

The steps involved in blood typing are as follow:

Collecting Blood:

- A venipuncture is performed from the vein of the individual being tested.

- The blood is then collected in a blood collection tube containing anticoagulant to prevent clotting.

Centrifugation:

- The collected blood sample is centrifuged to separate the red blood cells from the plasma and other components.

Preparation of Slides:

- A drop of patient serum or plasma and a drop of antisera containing known anti-A, anti-B, and anti-D antibodies are placed on separate glass slides or wells of a microtiter plate.

Mixing and Reaction:

- The patient's red blood cells are added to each slide or well containing the serum/plasma and antibodies.

- They are then gently mixed to allow the antibodies to react with specific antigens on the red blood cell surface.

Observation:

- After a brief period (usually a few minutes), the results can be observed:

- If there is agglutination (clumping) in both anti-A and anti-B wells but not in the anti-D well, the blood is type A+ or A-.

- Similarly, if agglutination occurs in both anti-A and anti-D wells but not in anti-B, the blood is B+ or B-.

- If agglutination occurs in the anti-D but not in the anti-A or anti-B wells, the blood is either O+ or O-.

- If there is no agglutination in any of the wells, the test needs to be repeated, as it may be invalid.

Interpretation of Results:

- To determine the ABO and Rh blood type, the pattern of agglutination and reactivity with different antibodies is evaluated using the observed reactions

- For example, if agglutination occurs in anti-A and anti-B wells (but not in anti-D), and there are no reactions with the reverse typing, the blood is either A+ or A-, depending on the Rh antibody reaction

Sometimes additional techniques such as cross-matching or further tests may be performed alongside or after blood typing to ensure compatibility in cases like transfusions.

Remember that blood typing is usually done by trained laboratory professionals, and it is essential to follow proper protocols to ensure accurate results and patient safety.