Lesson 4 6 ABO Grouping ABO System Major

Lesson 4 -6 ABO Grouping

ABO System �Major blood group system �Four groups: • A, B, AB, and O �Frequency • Differs slightly by country and ethnicity • See Table 4 -11

ABO System �Antigens • • • (Ag) A and B Present on RBCs and other tissue cells Products of inherited codominant genes Group O has neither A nor B antigen Detect antigens by forward grouping

ABO System �ABO • • • antibodies (Ab) Naturally occurring Ig. M Ab is present if Ag is missing Not well developed in newborns Detected by reverse grouping See Table 4 -12

ABO System � Importance • In transfusion, do not give patient antigen they do not have • Group O can be universal donor ABO Group Antigen on RBCs A A B B AB A and B O Neither A nor B

ABO Grouping Procedures �Safety precautions �Quality assessment �Principle of slide grouping • • Detects A or B antigens on RBCs Combine blood with anti-A and anti-B Agglutination indicates antigen is present See Table 4 -13

ABO Grouping Procedures �ABO slide grouping

ABO Grouping Procedures �Principle of tube tests • More sensitive than slide typing • Agglutination is positive test • Forward grouping detects Ag on patient cells �Patient cell suspension + anti-A and anti-B • Reverse grouping detects Ab in patient plasma �Patient plasma + A cells and B cells

Grade Agglutination � Number system, 0– 4+ • High number is strongest reaction • 0, w+, 1+, 2+, 3+, 4+

Interpreting Results ABO Group Forward Grouping Reverse Grouping Anti-A Anti-B A cells B cells O 0 0 + + 0 A + 0 0 + 0 B 0 + + 0 0 AB + + 0 0 0

Gel Typing

Gel Typing Report Form