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Liz's Blood Bank Module 1 > ABID: Basic and Intermediate > Flashcards

ABID: Basic and Intermediate Flashcards

1
Q

Abs other than ABO system (Rh, Kidd, Kell, MNSs, Lewis, P1, Duffy, Lutheran)

A

Unexpected Abs

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2
Q

Passively acquired Abs

A

?

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3
Q

Ab screen

- ABO type

A

Group O

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4
Q

Ab screen

- Required Ags to be present

A

Must have Ag positive cell for the following: D, C, E, c, e, K, k, Fya, Fyb, Jka, Jkb, Lea, Leb, P1, M, N, S, and s

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5
Q

Ab screen

- Zygosity of Ags present

A

Preferably homozygous

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6
Q

Ab screen

- Procedure for use of screening cells

A

2 or 3 cells used together to screen for all common unexpected clinically significant Abs

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7
Q

Ab panels

- ABO type

A

Group O

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8
Q

Ab panels

- Required Ags to be present

A

Cw, V, Kpa, Jsa, Lua (low frequency)

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9
Q

Ab panels

- Procedure for use of panel cells

A

8-20 cells used together to give a more specific pattern of reactivity for the different Abs; will often have cells taht can detect some of the “uncommon” Abs as well as common

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10
Q

How does 22% albumin aid in ABID?

A
  • Disperses charges around cells, ↓ zeta potential
  • Least sensitive
  • Longest incubation (30-60’)
  • Rarely used
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11
Q

How does LISS aid in ABID?

A
  • ↓ zeta potential and ↑ uptake of Ab by RBC in sensitization phase
  • More sensitive than albumin, not as sensitive as PEG
  • Diluent for gel methods
  • 10-30’ incubation
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12
Q

How does PEG aid in ABID?

A
  • Removes water in system → ↑ [Ab]
  • ↑ RBC sensitization
  • Can cause nonspecific aggregation of cells so you can NOT centrifuge at 37C (false pos)
  • More sensitive tahn LISS
  • 15-30’ incubation
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13
Q

How do enzymes ficin and papin aid in ABID?

A
  • Removes sialic acid residues and denatures/removes glycoproteins
  • Destroys some Ags and enhances others
  • Always compare enzyme result to non-enzyme result
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14
Q

How do DTT, 2ME, and AET aid in ABID?

A
  • Disrupt the disulfide bonds of IgMs when added to serum

- Destroys Kell and Lutheran system Ags (and some HTLA Ags) when incubated w/ cells

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15
Q

How do P1 and Lewis neutralization substances aid in ABID?

A

?

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16
Q

State 4 general steps of ABID substances

A
  1. Ab detection (IAT)
  2. ABID → panels, patient Ag typing
  3. Determine clinical significance → IgM vs. IgG
  4. Appropriate transfusion considerations are put into place → provide Ag negative blood
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17
Q

State Ab screen testing requirements according to AABB

A

Requires 37C incubation and use of Coombs

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18
Q

Autocontrol

- Procedure for testing

A

1 drop patient serum/plasma + 1 drop patient’s cell suspension

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19
Q

Autocontrol

- Significance of positive and negative results

A

Positive panel w/ negative AC → alloAb

Positive panel w/ positive AC → autoAb

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20
Q

Autocontrol

- Correlation to the DAT

A

If AC is positive, run a DAT → should be positive

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21
Q

List 5 “uncommon” Ags that may or may not be present on panel cells, but are not required to be ruled out on most panels

A

Cw, V, Kpa, Jsa, Lua

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22
Q

State 3 Ag exceptions to homozygous rule-outs

A
  • Kell can be ruled out heterozygously
  • In presence of anti-D (you have one positive for D), anti-C and anti-E can be ruled out heterozygously w/ a negative reaction
  • ?
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23
Q

Predict expected Ag type of a patient when identifying alloAbs and autoAbs

A
  • AlloAbs →all cells but AC will be negative

- AutoAbs → all cells including AC are positive

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24
Q

Select appropriate QC cells for rare antisera testing

A

For positive control, cells must be heterozygous

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25
Q

Why is the heterozygous expression of an Ag preferred for QC of rare antisera?

A

Heterozygous reactions are not as strong as homozygous, if QC can pick up on heterozygosity, it can pick up anything

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26
Q

Selected panels

- When to perform

A
  • Once you know which Abs you have, must have 3+ cells for each Ab which are Ag neg for all of the other Abs (positive proving cells can be heterozygous or homozygous)
  • Must have 3 cells that are negative for all Abs that have been ID’d
  • 3+3 cells can be from Ab screen, routine panel or selected cell panel
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27
Q

Pre-warm testing

- When to perform

A

To reduce or eliminate IgM cold autoAb interferences in testing

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28
Q

Pre-warm testing

- Procedure

A

Pre-warmm serum and cells in separate tubes → add serum to wash cells → incubate at 37C for 30-60’ → wash w/ warmed saline 3x → add IgG AHG

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29
Q

Pre-warm testing

- Limitations

A

Performed at hospital BBs

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30
Q

Pre-warm testing

- Interpretation of results

A

If negative, report as “cold auto/alloAb”; give XM-compatible blood using pre-warm technique

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31
Q

Enzyme-treated cells

- When to perform

A

?

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32
Q

Enzyme-treated cells

- Procedure

A

Removes sialic acid residues and denaturing glycoproteins

33
Q

Enzyme-treated cells

- Limitations

A

Performed at hospital BBs

34
Q

Enzyme-treated cells

- Interpretation of results

A

?

35
Q

Neutralization

- When to perform

A

When Lewis or P1 Abs are “masking” other Abs that may be underlying

36
Q

Neutralization

- Procedure

A

?

37
Q

Neutralization

- Limitations

A

?

38
Q

Neutralization

- Interpretation

A

Can be used to “prove” the Lewis or P1 Ab if pattern doesn’t prove

39
Q

Adsorptions

- When to perform

A
  • Presence of warm autoAbs
  • Presence of known Ab to high frequency Ag → remove high Ab when looking for other underlying alloAbs
  • Presence of multiple Abs
40
Q

Adsorptions

- Procedure

A
  • ZZAP-treated cells for adsorption will remove bound autoAb and free up Ag sites
  • ZZAP treatment of cells takes 30 minutes and then ZZAP must be washed off cells
  • Usually use 2 mL packed red cells for each adsorption (4-8 mL packed red cells)
41
Q

What is ZZAP?

A

A mixture of DTT which removes bound Ab

- Destroys Ags of Kell and Lutheran systems

42
Q

What is papin?

A

An enzyme which will enhance adsorption of Abs onto now open Ag sites
- Destroys Ags of Duffy and MNSs systems

43
Q

Adsorptions

- Limitations

A

Performed at reference lab

44
Q

Adsorptions

- Interpretation of results

A

?

45
Q

Elutions

- When to peform

A

To investigate Ab-coating RBCs (positive DAT) that has IgG coating cells

46
Q

Elutions

- Procedure

A
  1. Wash cells to remove unbound Ab
  2. Dissociate Ab from cell surface by adding acid
  3. Techniques release, concentrate, and purify Ab by changing attractive forces b/w Ag-Ab or structure of RBC surface
  4. Ab is freed into supernatant (eluate)
  5. Prepared eluate is tested against a panel of cells just as you would serum
  6. Original cells used to make eluate are discarded (can’t be used for anything else, “dead”, useless)
47
Q

Elutions

- Limitations

A

Performed at hospital BBs

48
Q

Elutions

- Interpretation of results

A

Results of eluate panel and patient history will determine cause of positive DAT

49
Q

Titrations

- When to perform

A
  • Commonly used to confirm HTLA Abs

- Quantify amount of Ab present

50
Q

Titrations

- Procedure

A
  1. Prepare two-fold serial dilutions of test serum
  2. Test erum dilutions against cells possessing corresponding Ag (note: use strongest expression of Ag for titer)
  3. Titer endpoint is the last tube w/ 1+ reaction (when confirming HTLA Abs, endpoint may be +w or +m reaction)
51
Q

Titrations

- Limitations

A

Performed at reference lab

52
Q

Titrations

- Interpretation of results

A

?

53
Q

DTT/2ME/AET

- When to perform

A

Used to eliminate acitivty of high frequency Abs by destroying Ags on cells to whcih Abs would attach

54
Q

DTT/2ME/AET

- Prcoedure

A

After treating cells, wash off remaining DTT or 2ME then test as normal w/ patient’s serum

55
Q

DTT/2ME/AET

- Limitations

A

Performed at reference lab

56
Q

DTT/2ME/AET

- Interpretation of results

A

?

57
Q

Cell separations

- When to perform

A

When patient has recently been transfused

58
Q

Cell separations

- Procedure

A
  • Microhematocrit retic separation

- Hypotonic washes for sickle cell patients

59
Q

Microhematocrit retic separation

A

“Retics” from patient will be lighter/less dense than older (donor) cells and will be in top layer of spun microhematocrit

60
Q

Hypotonic washes

A

Hb SS are resistant to lysis by hypotonic saline, whereas donor red cells containing Hb AA are lysed

61
Q

Cell separations

- Limitations

A

Performed at reference labs

62
Q

Cell separations

- Interpretation of results

A

?

63
Q

EGA or CDP treatment of cells

- When to perform

A

When cells have a positive DAT and need to be phenotyped

64
Q

EGA or CDP treatment of cells

- Procedure for EGA

A

EDTA glycine acid

  • EGA-treated cells destroy Kell system Ags
  • Can perform all other Ag typings, including AHG typings after cells have been “treated”
65
Q

EGA or CDP treatment of cells

- Procedure for CDP

A

Chloroquine diphosphate

  • Does not destroy Kell system Ags
  • Can only perform AHG typings (no direct typings)
66
Q

EGA or CDP treatment of cells

- Limitations

A

Performed at reference lab

67
Q

EGA or CDP treatment of cells

- Interpretation of results

A

?

68
Q

Purpose of performing a pre-warmed technique

A
  • May be used to reduce or eliminate IgM cold autoAb interference in testing
  • No reading at IS or 37C, hence, no IgM attachement
69
Q

Which Ags are destroyed, enhanced, and unchanged by treatment of enzymes?

A

Destroyed: Duffy, MNS
Enhanced: ABO, Rh, Kidd, Lewis, P, I
No change: Kell

70
Q

Name two common blood groups for which Abs can be neutralized

A

Lewis and P1

71
Q

3 adsorption techniques

A
  • Autoadsorption
  • Homologous adsorption
  • Differential adsorption (“triple”)
72
Q

When is an autoadsorption used?

A

Removes autoAbs by incubating patient’s serum w/ patient’s own cells

  • If patient has been recently transfused, you can’t use patient’s cells b/c donor cells could still be circulating
  • If patient’s Hct is too low, not enough cells for procedure
73
Q

Homologous adsorption

A

Use of donor cells whose phenotype matches the patient (must first phenotype the patient)

74
Q

When is homologous adsorption used?

A
  • When autoAb is suspected but use of patient cells isn’t available (patient’s Hct too low to do an autoadsorption)
  • Be used to remove a high frequency Ab to detect underlying alloAbs (?) (“selective” adsorption)
75
Q

When is a differential adsorption used?

A

When autoadsorption and homologous adsorptions aren’t an option

  • Patient has been recently transfused → can’t phenotype b/c of the mix of donor and patient cells
  • Patient’s cells have positive DAT → can’t phenotype b/c DAT will cause false positive reactions for AHG typings
76
Q

26

A

?

77
Q

Blood group systems whose Ags are destroyed by DTT/2ME/AET

A

Kell, Lutheran, HTLA

78
Q

What could cause a false negative Ag typing?

A

?

79
Q

What could cause a false positive Ag typing?

A

Postive DAT, centrifuging PEG at 37C

Liz's Blood Bank Module 1 (10 decks)

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