5. Pretransfusion testing Flashcards

1
Q

6 crucial steps for safe transfusion

A
  1. ID of patient and donor with appropriate sample collection
  2. Testing of donor sample
  3. Testing of patient sample and patient history review
  4. Selection of appropriate units
  5. Crossmatch
  6. Re-identification of patient before infusion
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2
Q

circle of safe transfusion

A

Patient wristband → BB sample → crossmatched units → transfusion request record → patient wristband

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3
Q

sample condition requirements (5)

A
  1. labelled correctly (2 identifiers); date; phlebotomist’s ID
  2. sufficient quantity
  3. minimal hemolysis
  4. appropriate site (not above IV)
  5. indelible ink used
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4
Q

records kept indefinitely

A

any difficulty in typing
clinically significant Abs

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5
Q

I, II and III screening cells are type — and have at least one cell…

A

O
homozygous for all clinically significant Abs

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6
Q

selection of appropriate units

A
  • type-specific preferred
  • use short-dated
  • conserve O for O patients
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7
Q

preferred form of XM

A

EXM

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8
Q

You can stop XM after negative IS or EXM if…

A

negative ABS
no hx of significant Ab

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9
Q

serves as final check for ABO/Rh compatibility

A

XM

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10
Q

major XM

A

pt plasma + donor cells

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11
Q

minor XM

A

donor plasma + pt cells

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12
Q

often to blame for XM incompatibility

A

autoAB

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13
Q

potential reasons for XM incompatibility (5)

A
  • autoAb
  • alloAb
  • error in unit selection/typing
  • excessive protein in pt serum
  • contaminants in test system
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14
Q

in emergencies, O= is given to….

A

females
males < 12 yo

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15
Q

in emergencies, O+ is given to…

A

males > 12 yo

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16
Q

Rh= patients that may receive Rh+ blood with pathologist approval

A

adult males
females > 50yo

17
Q

included on blood transfusion request form (4)

A

Pt 2 identifiers
Product requested
Physician
Transporter to patient care area

18
Q

included on label on issued units (3)

A

ID of intended recipient
Statement of compatibility
Unit or pool number

19
Q

read back includes… (5)

A

Intended recipient’s 2 IDs and ABO/Rh
Donor unit number and ABO/Rh
XM interpretation, if required
Special requirements
Date and time of issue (expiration)

20
Q

type for patient w/o hx of type

A

checktype

21
Q

reflex ABS procedures

A

ABS panel
antigen typing
2-unit XM (if sample labelled for transfusion)

22
Q

miniature automated tube tests

A

microtiter plate

23
Q

solid phase measures…

A

adherence of analyte to solid phase

24
Q

SPRCA

A

solid phase red cell adherence

25
Q

in solid phase, patient plasma is incubated with —— on a tray of wells containing….

A

LISS
bound known antigen

26
Q

added after incubation and washing of solid phase plate
why?

A

indicator cells with anti-IgG
allow visualization of Ab from plasma bound to antigen in solid phase

27
Q

solid phase plate is incubated at —– for —– mins

A

37°
30 mins

28
Q

positive solid phase reaction

A

indicator cells adhere to wells

29
Q

negative solid phase reaction

A

cell button; no adherence of indicator cells

30
Q

tests performed in solid phase in a well that is activated only

A

DAT
weak D
XM

31
Q

how is solid phase for XM, DAT, and weak-D different?

A

cells adhere to wall

pt plasma is added for XM
anti-D is added for weak D
indicator cells are added for DAT

32
Q

gel technology principle

A

antigen is suspended in gel medium
red cell agglutinates stay near top; nonagglutinated red cells pass through to the bottom

33
Q

how are gel IAT and gel DAT different?

A

IAT: IgG is in the gel
DAT: anti-IgG is in the gel (no C3)

34
Q

advantages of alternative tech (7)

A
  • Standardized technique – consistent, reproducible and stable end points
  • Less subjectivity
  • Stability of test results
  • Decreased sample volume
  • Enhanced or equivalent sensitivity
  • Automation is available
  • Larger batches (ie Red Cross)
35
Q

disadvantages of alternative tech (7)

A
  • Cost (equipment, training, reagents, etc)
  • Some methods do not allow detection of both IgM and IgG, or cannot distinguish between them (ie Gel)
  • Gel has difficulty with rouleaux, fibrin — false positives
  • May not provide information on the phase and temperature of reactivity of antibodies
  • Increased sensitivity my cause insignificant antibodies to be detected
  • Solid phase requires a wash step
  • Long TAT, especially with gel