Anti-a1 Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Anti-a1 and links to relevant pages within the course.
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| The most common source of Anti-A1 is: | View Page |
| Match the blood type on the left with the appropriate description on the right. | View Page |
| A2B patients have or may have which of the following: | View Page |
| Red Cells Tested With Known AntiseraSerum Tested With Known Red CellsInterpretation of ABO Group Anti-AAnti-BAnti-A,BA1 CellsB Cells 4+4+4+1+0?Using the information provided above, select the correct ABO group. | View Page |
| A1 and A2 The most common classifications are A1 and A2. These account for over 99% of group A bloods. Of this 99%, A1 compromises approximately 80%. Commercial anti-A typing serum does not differentiate between A1 and A2 cells. A1 cells contain “A” antigen and “A1” antigen. A2 is not really a unique antigen. It is thought to be simply “A” antigen with no “A1” antigen. Several preparations are available that will react with A1 cells, but not other subgroups of A. An extract of the seeds of the plant, Dolichos biflorus has specific anti-A1 activity. “Absorbed anti-A” serum can also be prepared. To do this, the anti-A from group B people is absorbed with A2 cells. Anti-A is removed and a second antibody that reacts only with A1 cells remains. Anti-A1 can also be found as a separate antibody in the sera of A2 and A2B individuals. | View Page |
| Why Knowledge of A Subgroups Is Important For Laboratorians For the most part, subgroups are merely of academic interest, but occasionally they present clinical problems. The antigen may be so weak that it is not detected and the red cells are mistyped as group O. This is especially dangerous if the cells are those of a donor. Problems may arise because the serum of an A2 or A2B, A3 or Ax individual might contain anti-A1. This antibody may be detected in serum typing and cause confusion. You would not expect to find a person with A antigen on his red cells and anti-A in his serum. Anti-A1 is produced by about 1-2% of group A2 persons and about 25% of group A2B persons. Subgroups may be determined by reactions with antisera as seen in the table on the next page. | View Page |
| Reaction of Red Cell Subgroups With Known Antisera Subgroup Patient Red Cells Tested with Known Antisera Anti-A1 in Serum? Anti-A Anti-A1 Anti-A,B A1 4+ 4+ 4+ No A2 4+ 0 4+ Yes, 1-2% A3 2+, mixed field 0 2+, mixed field Yes, but % not available + = agglutination (graded 1+ to 4+)0 = no agglutination | View Page |
| Why may the presence of A subgroups cause ABO typing discrepancies? | View Page |