RH GROUP PPT 2 Flashcards
(46 cards)
(DETECTION OF RH ANTIBODIES AND ANTIGEN)
_______: usually produced following exposure of the individual’s immune
system to foreign RBCs, through either transfusion or pregnancy
Rh Antibodies
(DETECTION OF RH ANTIBODIES AND ANTIGEN)
May show _______ Reacting preferentially with RBCs possessing double- dose
Rh antigen.
For example, anti-E may show 3+ positive reactivity with E+e- RBCs
versus 2+ positive reactivity with E+e+ RBCs
dosage
(DETECTION OF RH ANTIBODIES AND ANTIGEN)
IgG1, IgG2, IgG3, IgG4 subclasses of Rh Ab have been reported.
_____ AND ______ – greatest clinical significance because the reticuloendothelial system
rapidly clears RBCs coated with IgG1 and IgG3 from the circulation.
IgG1 and IgG3
(DETECTION OF RH ANTIBODIES AND ANTIGEN)
_____ Rh Ab are formed initially, followed by ___
IgM ; IgG.
(DETECTION OF RH ANTIBODIES AND ANTIGEN)
Individuals with low-titer Rh Ab may experience ________ (secondary) Ab response if exposed to same sensitizing Ag.
anamnestic
(DETECTION OF RH ANTIBODIES AND ANTIGEN)
_______ blood must be provided to any patient with history of Rh-antibody
sensitization.
Antigen-negative
(DETECTION OF RH ANTIBODIES AND ANTIGEN)
Rh Ab do not bind _______
complement
(DETECTION OF RH ANTIBODIES AND ANTIGEN)
For complement to be fixed (To activate complement cascade): two _________ must attach to an RBC antigen in close proximity to each other
IgG immunoglobulins
(Rh Antibodies in Pregnancy)
Rh antibodies are primarily _____ and can traverse the placenta and because Rh antigens are well
developed early in fetal life, Rh Ab formed by Rh-negative pregnant women cross placenta and coat fetal RBCs carry corresponding Ag.
IgG
(Rh Antibodies in Pregnancy)
_____ was the most frequent cause of HDFN
anti-D
(RH TYPING REAGENT)
____ may be high-protein-based or low-protein- based, saline based, chemically modified, monoclonal,
or blends of monoclonals.
Reagent
(RH TYPING REAGENT)
_________ – contain IgM immunoglobulin, first typing reagents available to test for D antigen.
________: low-protein-based, used to test cells already coatedwith IgG antibody
_________: limited availability, cost of production, lengthy incubation time. An IgM immunoglobulin, it
cannot be used for weak-D typing.
Saline reactive reagents ; Advantage ; Disadvantage
(RH TYPING REAGENT)
___________ - contain IgG anti-D.
_______ containing high-titer D- specific antibody was used as raw material.
Potentiators of _______ and macromolecular additives such as _______ OR ________ were
added to the source material to optimize reactivity in standard slide and rapid tube tests to allow for direct agglutination of red cells using an IgG anti-D.
High-protein anti-D reagents ; Human plasma ; bovine albumin ; dextran or polyvinylpyrrolidone
(RH TYPING REAGENT)
Major advantages of high-protein anti-D reagents
- Reduced incubation time
- Ability to perform weak-D testing and slide typing with the same reagent.
- Reagent is polyspecific.
- More than one clone of anti-D is produced by immunized human donors, thus recognize multiple epitopes on
RhD protein.
(RH TYPING REAGENT)
Disadvantages of high-protein anti-D reagents
a false-positive reaction would be obtained because the RBCs would agglutinate on their own
(RH TYPING REAGENT)
______________ by breaking disulfide bonds that maintain antibody’s rigid shape.
This allows antibody to relax and span distance between RBCs in low- protein medium.
Chemically modified reagents can be used for both ____ and _____ testing and do not require a separate, manufactured Rh control as long as the samples type as A,B,or O.
Sample test AB Rh-positive or when Rh test is performed by itself, separate _____ control or _________ control must be used to ensure observed reactions are true agglutination, not a result of spontaneous agglutination.
Chemically modified the IgG anti-D molecule ; tube and slide ; saline or 6% to 8% albumin
(RH TYPING REAGENT)
____________: reagents are derived from single clones of antibody-producing cells.
Rh monoclonal antibodies
(Rh monoclonal antibodies)
- Antibody-producing cells are hybridized with _______ to increase their reproduction rate, thereby maximizing their antibody- producing capabilities.
- ___________ are usually combination of monoclonal anti-D reagents from several different
clones to ensure reactivity with broad spectrum of Rh-positive RBCs.
myeloma cells ; Monoclonal anti-D reagents
(Rh monoclonal antibodies)
- Some companies blend _____ and ______ to maximize visualization of reactions of immediate spin testing to allow indirect antiglobulin testing for weak D antigen with same reagent.
- Monoclonal blends can be sued for _____, _____, ____ and _______ testing. Not human derived so it lacks potential transmitting infectious disease.
IgM and IgG anti-D ; slide, tube, microwell, and most automated Rh
FALSE REACTIONS WITH RH TYPING REAGENTS : FALSE-POSITIVE
LIKELY CAUSE:
1. Cell suspension too
heavy
2. Cold agglutinins
3. Test incubated too long
or drying (slide)
4. Rouleaux
5. Fibrin interference
whats the corrective action??
CORRECTIVE ACTION:
- Adjust suspension, retype
- Wash with warm saline, retype
- Follow manufacturer’s
instructions precisely - Use saline-washed cells, retype
- Use saline-washed cells, retype
FALSE REACTIONS WITH RH TYPING REAGENTS : FALSE-POSITIVE
LIKELY CAUSE:
6. Contaminating lowincidence antibody in
reagent
7. Polyagglutination
8. Bacterial contamination
of reagent vial
9. Incorrect reagent
selected
10. Centrifugation too long
11. rpm too high
whats the corrective action??
CORRECTIVE ACTION:
- Try another manufacturer’s
reagent or use a known serum
antibody - See chapter on polyagglutination
- Open new vial of reagent, retype
- Repeat test; read vial label
carefully - Repeat test using shorter
centrifugation time - Repeat test using lower rpm
FALSE REACTIONS WITH RH TYPING REAGENTS : FALSE-NEGATIVE
LIKELY CAUSE:
1. Immunoglobulin-coated
cells (in vivo)
2. Saline-suspended cells
(slide)
3. Failure to follow manufacturer’s directions precisely
4. Omission of reagent
manufacturer’s directions
5. Resuspension too vigorous
CORRECTIVE ACTION:
- Use saline-active typing reagent
- Use unwashed cells
- Review directions; repeat test
- Always add reagent first and
check before adding cells - Resuspend all tube tests gently
FALSE REACTIONS WITH RH TYPING REAGENTS : FALSE-NEGATIVE
LIKELY CAUSE:
6. Incorrect reagent selected
7. Variant antigen
8. Reagent deterioration
9. Incorrect reagent selected
10. Centrifugation too short
11. rpm too low
CORRECTIVE ACTION:
6. Read vial label carefully; repeat
7. Refer sample for further
investigation
8. Open new vial
9. Repeat test, read vial label
carefully
10. Repeat test using longer
centrifugation time
11. Repeat testing using higher rpm
(CLINICAL CONSIDERARTION: TRANSFUSION REACTION)
Detection of _____ needs careful medical history that reveals RBC exposure through pregnancy or transfusion of products
containing RBCs.
anti-D
