Test 3B Flashcards
What are the 7 parts of a Compatibility Test?
- Request
- Receipt of acceptable blood sample.
- Type & Screen
- History
- Xmatch procedure
- Select transfustion blood
- Perform Xmatch
- Label tubes
List the blood groups that are known to cause hemolysis.
ABO P Lewis Kidd Vel
Why is patient ID an integral step in blood transfusion.
If the patient is not correctly identified prior to obtaining the sample, an incorrect blood type may be obtained or an antibody present may be missed. This could cause death following transfusion.
What is an AGT?
Antiglobulin Test
What is the purpose of the AGT?
To detect bound IgG and/or complement on the red blood cells.
Name 3 types of AHG reagent.
Polyspecific (IgG and C3d)
Monospecific IgG
Monospecific C3d
How does AHG work?
Any cells coated with Ab will be complexed with AHG, and the clumps will form macroscopic or microscopic
What are the 2 ypes of AHG tests?
DAT and IAT
What is DAT?
direct antiglobulin test
What is IAT?
indirect antiglobulin test?
Which tests are in vivo and which are in vitro?
DAT - in vivo
IAT - in vitro
What are unexpected antibodies
Antibodies to red cell antigens that are not expected (other than ABO)
What is the purpose of the antibody screen?
To detect unexpected red cell antibodies in the patient’s serum or plasma?
What types of cells are used in antibody screening and identification?
group O
RH positive and negative
What are enhancement reagents?
Substances added to the testing system to increase the binding of antigens and antibodies
Name 3 enhancement reagents
Albumin
LISS
polybrene
PEG
What are Coombs Control Cells and what is their purpose?
RBCs coated with human IgG antibody that are added to a negative AHg tube to ensure proper functioning of the AHG reagent.
What does it mean if the Coombs Control Cells do not agglutinate?
AHG reagent was omitted or inactivated, or the test system was not washed adequately to remove all protein
Describe the purpose of the Autocontrol and what it means if it is positive
Testing of the patient’s serum or plasma with their own red blood cells to determine if an autoantibody is present. If it is positive, the patient may have free autoantibody in their serum or plasma
What test do you run if the autocontrol is positive?
DAT
What tests are performed on a patient’s sample in order to administer unites of packed RBCs?
ABO/Rh
Ab screen
Crossmatch
If an antibody screen on a patient is negative, what is the chance that a crossmatch would be INCOMPATIBLE?
Less than 1% chance
How are enzymes helpful in antibody identification?
Enzymes destroy Duffy and MNS antigens. Enzymes also enhance some reactions (such as Rh)
What is a major crossmatch?
Patient’s serum or plasma with donor RBCs
