Lab 2: 2/2 ABO Typing Flashcards
is defined as using reagent red cells with known ABO antigens and testing the serum of the patient for ABO group antibodies.
Reverse grouping (serum typing)
The only Rh system antigen routinely tested for is the____ antigen.
D
Generally, clotted or anticoagulated blood samples may be used for ABO testing, with a preferred sample being ______.
EDTA
The red cells may be suspended in autologous serum, plasma, or saline, or they may be washed and resuspended in saline.
If specimen cannot be tested right away, what temp should it be stored at?
2-8oC
-Alternatively, serum or plasma can be separated from red blood cells and stored frozen.
What type of specimens should not be used?
Blood specimens exhibiting gross hemolysis or contamination
Why should samples not be drawn in tubes with neutral gel separators?
can cause false-positive
Can hemolyzed samples be used?
no
Clotted specimens or those collected in EDTA should be tested within ___ days of collection.
7
The antisera reagents should be stored at _______C. And should not be used if turbid.
2oC – 8oC
What does the cells reagent contain?
-2-4% suspension of pooled C-D-E red blood cells suspended in a buffered solution to retard hemolysis and/or loss of antigencity
-EDTA is added to inhibit complement activation and prevent hemolysis when RBCs are tested with fresh serum.
What temp should the cells reagent be stored at?
1-10oC when not in use.
Do not freeze or expose to elevated temperatures.
What should be done to the vial before using the cells reagent?
suspend by gently inverting each vial several times.
How long should all tubes be centrifuged for?
10 seconds
refers to mixed reactions during cell typing where two distinct cell populations are present
Mixed-field agglutination
How often should quality control of reagents be perfomed?
each day
Quality control:
Anti-A
Anti-B
Anti-A,B
should be tested with….
A1, A2, B and O cells
Tests should be read immediately by the “__________” procedure. Excessive agitation may disrupt weak agglutination and produce false negative results.
tip and roll
excessive g force during centrifugation will lead to…
difficulty in resuspending the cell button
Inadequate centrifugation may result in….
agglutinates that are easily dispersed
Causes of false-positive or false-negative results?
-contamination of test materials
-improper reaction temperature
-improper storage of materials
-omission of test reagents -certain disease states
Why should tests involving cord/neonatal red cells be interpreted with particular care?
ABO antigens are not fully expressed at birth
Decreased antibody activity to A and B antigens has been reported with samples from…
debilitated or elderly patients or patients who are less than 6 months old.
Why are better results obtained with fresh samples?
The expression of certain red cell antigens may diminish in strength during storage, particularly in EDTA and clotted samples.
What may interfere with serum grouping tests?
Non-ABO-related agglutination
