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18 Cards in this Set
- Front
- Back
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How is AHG made?
How does the test work? |
inject a non-human with IgG, C3d, C3b and collect the Ab's (AHGs) that are then created.
AHGs bind to human globulins (proteins) |
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What are the differences between ABO and AHG testing? Define Ab's.
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ABO = IgM = immediate spin/ complete agglutination
AHG = IgG = need additional steps/non-agglutinant |
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AHG testing determines the presence of what Ag's?
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Rh Ag's
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AHG testing detects:
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IgG Alloab's
IgG Autoab's Complement components |
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Which AHG test is used for cells in vivo?
Which for in vitro? |
in vivo: DAT (direct antiglobulin test)
in vitro: IAT (indirect) |
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Define the 2 types of AHG reagents:
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Polyspecific AHG: IgG, C3b & C3d
Monospecific AHG: IgG |
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Define the 2 ways AHG reagent can be prepared:
3 advantages of both |
Polyclonally: can make both polyspecific & monospecific; prevents prozone (excess Abs); detects IgG subclasses
Monoclonally: easy to produce, less false +'s; less specific (recognizes only 1 epitope) |
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Is the DAT a routine test?
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No
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IAT can be influenced by what 3 things:
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LISS & Albumin
Complement activity |
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What are 4 reasons for a positive DAT test?
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1. RBCs coated in vivo (RA, Lupus)
2. Drugs (aspirin) 3. Delayed transfusion reaction 4. HDFN |
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DAT tests are done on what samples?
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EDTA
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Is the IAT a routine test?
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Yes, for blood transfusions
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Name three potentiators/mediums used in the IAT?
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LISS
Albumin PEG |
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What are the levels needed for detection by the DAT and the IAT?>
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DAT: 100- 500 IgG
IAT: 100-200 IgG |
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Name 7 factors that can affect the AHG tests:
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Ratio of serum to cells
Medium used (albumin, LISS, PEG) Temp Incubation Time Washing Saline Centrifugations |
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3 most common error sources:
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1. inadequate washing
2. nonreactive AHG reagent 3. Failure to add AHG reagent |
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Negative AHG results must be checked how?
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Adding check cells (IgG sensitized cells)
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Name 2 clinically insignificant auto Abs:
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warm/cold reacting AutoAbs
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