Lab quiz 3 Flashcards
Purpose of Universal precautions?
Protect workers and samples from blood borne pathogens
What happens if suspension is too light?
Re-spin suspension to separate cells from suspension
Remove saline
Resuspend cells
What happens if suspension is too heavy?
Add more saline
Mix thoroughly
Agglutination grading
0: no agglutination
1+: small agglutination cloudy background
2+: Medium agglutinates, clear background
3+: several larger agglutinates, clear background
4+: one solid agglutinate, clear background
Forward grouping
Detect antigens on patients RBCs with known reagent antisera
Reverse grouping
Detect antibodies in patient plasma using known reagent RBCs
ABO discrepancies
unexpected reactions that occur in forward or reverse grouping
What is to be done with ABO discrepancies?
Give O type blood is resolution isn’t found
What is the most immunogenic antigen outside of the ABO system?
D antigen
When can Anti-D be produced?
When an Rh-negative individual is exposed to Rh-positive RBCs
Via pregnancy or transfusion
Why is anti-D harmful?
Could cause hemolytic transfusion reactions and HDN
How can D-antigen be detected?
Direct agglutination (immediate spin phase)
Weak D test?
When D antigens are reduced in quantity
involved incubation and antihuman globulin reagent
(AHG Phase)
When is weak D test needed?
When typing donor units for transfusion and when a newborn whose mother is Rh-negative
If patient is Rh-negative?
D test and weak D test are negative
Rh immune globulin
Can protect mother from making anti-D
Antibody screen
An additional test to go along with ABO and Rh
Patient serum tested for antibodies
What blood type are screening cells
Type O
If screening test is positive?
Further testing is needed
IAT
Indirect Antiglobulin Test
Tests for in vitro sensitization of RBCs
If the auto control for IAT is positive?
We can suspect warm auto antibodies or recent transfusion
If screening cells are positive and auto control is negative?
Alloantibody to high incidence antigen/multiple antibodies are suspected
DAT
Direct antibody test
detects in vivo sensitization of RBCs with IgG/ complement components
Difference between DAT and IAT?
Incubation not needed for DAT
Clinical conditions of in-vivo coating of RBCs
HDN
HTR
AIHA
What is needed for DAT
Polyspecific (has IgG and anti-C3d)
Monospecific (Anti-IgG
and Anti-C3d
Immediate spin crossmatch
Tests ABO compatibility
Patient plasma and donor red cells
For patients who lack significant antibodies or don’t have record of such antibodies
Antiglobulin crossmatch
To confirm compatibility between patient plasma ad donor red cells
For people who currently have significant antibodies or have prior record of such antibodies
When is antibody identification needed?
If antibody screen is positive
How many O blood groups are needed for antibody id?
11-20 O red blood cells
What blood group systems are used?
Kidd, Duffy, Lutheran, Rh, MNS
IgM class antibodies
react at low temp
cause agglutination at immediate spin
IgG antibodies
React best at AHG phase
Which are IgM antibodies
N,I,P1
