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what are the 2 stages of agglutination
1. coat cells (sensitization)
2. formation of bridges (Ab & RBCs)
What is the phase that has pt serum + 2-5% RBC solution in a tube, centrifuge and examine?
Immediate spin phase
WHat phase duplicates body temp, takes mixture, incubates at 37C for a specified time, centrifuge and examine?
What is the indirect antiglobulin test (aka Coombs test, Antihuman globulin)?
wash mix of pt serum and RBC solution to remove unbound Ab
Add AHG (look for something coating RBCs)
centrifuge and examine
What is the test where UNCOATED RBC + Ab is put together, washed, AHG added and examined?
INDIRECT Antiglobulin test
What is the test where you take the RBC's directly from the pt, wash unbound Ab, add AHG and examine?
DIRECT Antiglobulin test
What 3 uses can you use the IAT for?
1. check for unknown Ab (RBCs + known Ag profile-ie Ab scrn)
2. check for unknown RBC Ag (serum + known Ab specif--ie RBC Ag test)
3. check for rxting unknown Ag AND unknown Ab--ie crossmatch
What is the specific AHG that detects RBC coated with either IgG or C3d and may detect other Ig?
What is the AHG that detects IgG and light chains assoc c other Ab classes (IgM, IgA)?
Anti-IgG and anti-IgG (heavy chains)
What is the AHG that detects complement components, is good for IgM related hemolysis and certain WAIH w/o IgG?
What are the 3 specificities of AHG?
1. Anti-IgG, C3d
2. Anti-IgG, anti-IgG (heavy chains)
3. Anti-C3b, -C3d
What test do you do to make sure your DAT or IAT reagent is working if you get a negative DAT or IAT?
How does the Coomb's control work?
add IgG coated RBCs to the mix you had for the IAT
if test negative, bad AHG or didn't add AHG
What are the 5 traits of a warm reacting Ab?
2. clin sig
3. require exposure
4. cause HDN
5. cause HTR
What are the 5 traits of a cold reacting Ab?
2. not clin sig
3. naturally occurring
4. no HDN
5. no HTR
What is the one exception to the rule of the warm and cold reactive Ab?
ABO, it's cold reactive and IgM but clin sig
Name the blood groups enhanced by enzymes like papain and ficin?
Lewis Is A Rhotten Peeing Kidd
ABO, Lewis, I/i, P, Rh, Kidd
What are type I ABO blood group chains composed of and where are they found?
Found in secretions.
What are the type II ABO blood group chains composed of and where are they found?
Found on RBCs
What does an Se gene add to a Type I chain and where?
Adds FUCOSE to type I chains at the TERMINAL GALACTOSE
What happens to the amount of H Ag when you make A or B Ag?
more A or B, less H (reciprocal relationship)
What are the two types of ABO testing?
forward grouping (cell typing)
reverse grouping (back or serum typing)
Which ABO test uses pt's RBC (Ag), add known anti-A and anti-B sera?
Forward grouping (tells you pt RBC type)
Which ABO test uses pt's SERUM/plasma (Ab), add known A1 and B RBCs?
Reverse grouping (tells you pt Ab)
Serum and cell typing are required unless what 2 reasons?
1. baby < 4 months old
2. reconfirming testing done elsewhere (just do cell/fwd typing)
What are the main Ag probsin ABO typing discrepancies?
1. Lack of expected Ag
2. Presences of unexpected Ag
What reasons do you get lack of expected Ag in ABO typing?
1. A or B subgroups
2. txp or transfusion
What reasons do you get presence of unexpected Ag in ABO typing?
1. Acquired B phenotype-colon ca, G- sepsis
2. recent marrow/stem cell txp
3. nonspecific polyagglutination
What are reasons you get lack of expected Ab in ABO typing?
2. immunocompromised, elderly, neonate
3. really high [ ] of Ab-->prozone effect
3. txp or tranfusion
What are reasons you get unexpected Ab in ABO typing?
1. Anti-A1 (from A2 pts)
3. cold auto/alloAb
4. txp or transfusion
When bact deacetylate A so it looks like B (term galactose) and the remaining galactosamine cross reacts with Anti-B what is that?
Acquired B phenotype
How do you fix an acquired B to get the right results?
Acetic acid (re-acetylates)
Autoincubation (no rxn)
Bs-1 lectin (no rxn, only rxn with real B)
What type of phenotype rxts with a particular form of Anti-A?
B(A) phenotype, to fix just use diff Anti-A
How does the ABO typing look in Bombay?
Ab scrn is WILDLY + and all units incompatible
How does the ParaBombay ABO typing look?
Reverse: H and A or B Ag (unless group O), have anti-H in serum
How is Le b Ag made?
1rst: Se gene adds fucose to term galactose->makes type I H
2nd: Le gene adds fucose to subterm GlcNAc->Le b
b is the 2nd letter of the alphabet, b goes on 2nd
Which Le adsorbs better to RBC surface?
Le b is BETTER, that's why most adults that are Le and Se are Le (a-b+)
If pt is Le (a-b+) do they have anti-Le a?
no, they still have Le a too, just not detected on RBC surface
What phenotype has hemolytic anemia with stomatocytes, associated altered activity of S, s and U and no Rh Ag at all?
What type of Ab is Kidd?
Warm reacting IgG
Very good at fixing complement (unusual for IgG)
What 2 blood groups show dosage?
Duffy and Kidd
may not react at all with heterozygous Kidd Ag; react VERY strongly to homozygous Kidd Ag
What type of glycophorin carries M or N Ag?
Glycophorin A (these are the 1rst 2 letters in the group, A is 1rst)
What are the M and N Ab?
cold IgM (Anti-M gen insig but has been assoc w HDN)
What is the Ag that is on glycophorin B that has the same term 5 AA as glycophorin A's last 5?
What MNSs Ab is induced by formaldehyde sterilization of the hemodialysis machine?
Anti-N, formaldehyde modifies N Ag
What is the relationship of Kx ot Kell Ag?
Kell Ag decrease, Kx increases (Kell Null phenotype aka K0)
What are the consequences of Kell incompatibility?
Severe HTR acute or delayed, EXTRAvascular
What is the complete absence of Kx Ag and markedly decreased but not absent Kell Ag, no anti-Ku, hemolytic anemia and acanthocytes?
What dz is McLeod phenotype assoc with?
Chronic Granulomatous Disease
-X linked recessive
-NADPH oxidase deficient
-organisms phagocytized but not killed
-catalase + organisms (Staph)
What blood group has a high freq, refractile immune complexes andis neutralized by guinea pig urine?
What Ag is assoc with Parvovirus B19?
P Ag is the Point of entry for Parvovirus (P Ag is Parvovirus B19 receptor)
What type of Ab is assoc with Paroxysmal Cold Hemoglobinuria?
IgG--biphasic hemolysin, binds in cold, hemolyzes when warmed
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