Blood Grouping Procedure

Blood is composed of cells suspended in a liquid. The liquid portion is the plasma, from which therapeutic fractions and derivatives are made.


Suspended in the plasma are three types of cells:

• Red cells carry oxygen
• White cells fight infection
• Platelets stop bleeding in injuries

The most common type of grouping is the ABO grouping. Red Blood Cells have a protein coat on their surface which distinguishes them. According to this blood is divided into four groups:

• A (A oligosaccharide is present)
• B (B oligosaccharide is present)
• AB (A and B oligosaccharides are present)
• O (neither A nor B, only their precursor H oligosaccharide present)

There are subtypes under this grouping (listed as A1, A2, A1B or A2B…) some of which are quite rare. Apart from this there is a protein which plays an important part in the grouping of blood. This is called the Rh factor. If this is present, the particular blood type is called positive. If it is absent, it is called negative. Thus we have the following broad categories:

• A1 Negative (A1 -ve)
• A1 Positive (A1 +ve)
• A1B Negative (A1B -ve)
• A1B Positive (A1B +ve)
• A2 Negative (A2 -ve)
• A2 Positive (A2 +ve)
• A2B Negative (A2B -ve)
• A2B Positive (A2B +ve)
• B Negative (B -ve)
• B Positive (B +ve)
• O Negative (O -ve)
• O Positive (O +ve)