ABO TESTING UPDATED ACTUAL QUESTIONS AND CORRECT ANSWERS

ABO TESTING UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS

Question:
1. abo antigens and antibodies
Answer:
Antigens on the RBC and antibodies are in the serum

Question:
2. red cell suspension
Answer:
o 2-5% suspension of RBC needed to perform most of the blood bank tests o Use red or lavender tube o
Notice that steps #1-#6 in the Laboratory Manual are the procedure for "washing" the red cells. The
purpose of these steps are to remove any excess serum from the red cells and provide cells that are "clean"
and suspended only in saline. o The 2%-5% indicates that the concentration of the cells in saline is diluted
5% of what the cell concentration is in a few drops of cells taken directly from the red top or EDTA tube

Question:
3. forward typing
Answer:
patient RBC's tested against commercial antibodies (or antisera Anti-A and Anti-B)
aka cell grouping
determine blood type by identifying what antigens are on the ABO

Question:
4. forward typing procedure notes

, Answer:
ALWAYS read the label of the anti-sera or cells that you are using
Before using anti-sera or cells make sure that they are WELL MIXED
In these beginning stages test only 1 sample at a time. (as you gain experience with these procedures you
may increase your pace but for right now please concentrate on completing testing on ONE sample before
moving to the next patient)
ALWAYS, ALWAYS label tubes accurately. Check the label on the tube before introducing anti-sera or
cells. (note: clerical errors are the #1 source of mistakes found in the blood bank lab)
As a matter of technique: it is always best to add the anti-sera or serum to the test tube first - then add the
cells Mix samples well before centrifuging
NEVER open or stop the centrifuge before it comes to a complete stop. Doing so is extremely poor
technique and is very dangerous!
Pull samples from the centrifuge in the order in which you wish to "read" them i.e. Anti-A, then Anti-B,
then Anti-A,B
After you centrifuge each test tube the red cells will come together in the form of a "button" of cells at the
bottom of the tube. To analyze the cells and check for "agglutination" you gently shake the tube then tilt it
side ways and look for how the button dislodges and whether aggregates of RBC are seen. You then record
your result using the Agglutination Grading System (i.e. neg, 1+, 2+, 3+ or 4+)
Remember to always Completely Dislodge the button before recording your result.
Do NOT "over shake" the sample - weak or even strong positive results may become negative if you shake
too vigorously or too long.
Constantly observe the RBC button as you dislodge it through the concave mirror provided on the
agglutination lamp.

Question:
5. reading forward typing
Answer:
: Remember that antibodies will ONLY react with their specific antigens. Therefore, a positive result
means that a specific antigen-antibody reaction occurred and the type of antigen on the RBC is reflective
of the patient's ABO blood type.

Question:
6. forward typing chart
Answer:




Question:
7. reverse typing
Answer:
commercial reagent RBC's/antigens tested with patient serum
o Reverse typing or serum grouping o Determine blood type by identifying what antiboides are in their
serum o Use serum and manufacturer's RBC-A1 and B cells § The type of antibody is being detected §
ABO are naturally occurring antibodies so they will be naturally in the patient's serum so they will have
the antibody to what they lack