Chapter 8 Flashcards by Erin groat

Landsteiner was the first too

perform ABO testing

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Ottenberg stressed the important of

crossmatch before transfusions

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When are cold reactive antibodies significant?

Hypothermia

Dropping OR Temp

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Alloantibodies that react at 37 degrees/AHG are capable of

causing decreased survival of transfused RBCs

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Alloantibodies are formed by

exposure to foreign RBCs by previous transfusion and/or pregnancy

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When are alloantibodies clinically significant?

When they cause HTR or HDNF

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What is the purpose of AHG testing?

To detect RBCs sensitized by IgG alloantibodies, IgG autoantibodies, and/or complement

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How does the AHG reagent work?

Any cells coated with antibody will be complexed with AHG, and clumps will form (macro or microscopically)

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What are the two type of AHG tests

Direct Antiglobulin Test (DAT)

Indirect Antiglobulin Test (IAT)

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Polyspecific AHG reagent contains

anti-IgG and and anti-C3d (complement)

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Monospecific AHG reagent contains

EITHER
anti-IgG or
anti-C3d

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This test detects in vivo sensitization of RBCs w/ IgG and/or complement (like a snapshot of what is happening in the body right now )

Direct Antiglobulin Test (DAT)

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This test detects in vitro sensitization of RBCs (like a what if scenario)

Indirect Antiglobulin Test (IAT)

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The DAT test is used for

HDN
HTR
AIHA

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The IAT test is used for

Compatibility testing, antibody screen, antibody ID, RBC phenotyping

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Coombs control check cells usually have avery potent anti-___.

anti-D

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What are Coombs Control Cells used for?

To ensure that AHG was not accidently omitted or inactivated.

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If CCC cells are negative the test is

invalid and must be repeated

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What is a major crossmatch?

Testing a recipient serum against donor RBCs

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What is a minor crossmatch?

Testing of the recipients RBCs against donor serum.

NO LONGER PERFORMED (per AABB standards)

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What are the elements of Pre-transfusion testing?

ABO Forward
Rh
ABO Revese
Antibody Screen
Crossmatch

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Gel technology require serum/plasma?

Plasma

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Tube testing works better with serum/plasma?

Serum

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What can be used to break up small clots from anticoagulated patients on heparin?

Thrombin or protamine sulfate

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What must be included on the label of patient blood samples?

``` 2 uniques identifiers Date of Collection Phlebotomists name/ID Legible Indelible Ink if handwritten ```

Which antibodies are known to cause hemolysis?

``` ABO P Lewis Kidd Vel ```

Lipemic blood samples may be

rejected

How long can a blood sample be pre-transfusion tested before the transfusion?

3 days if: The patient has been transfused in the last 3 months The patient has been pregnant in the last 3 months The history is uncertain or unavailble

Blood samples should be stored after a transfusion

1-6 degrees C for a minimum of 7 days after transfusion along with segments

Reviewing previous records for previously detected antibodies helps in avoiding

amnestic response | possible delayed hemolytic sequellae

What is the goal of the antibody type and screen?

To detect antigen-antibody interaction

What is GEL negative and GEL positive?

Negative: button of cells at the bottom Positive: clump of cells at the top 1+, 2+, 3+ in middle

What is microplate positive and negative?

Negative: no adherance Positive: Adherance to cell wall

What type of technolody do microplates use?

Solid phase technology

What types of reagents should be used for Rh control?

Commerical Rh control | 6% albumin

The Rh control should always be positive/negative

Negative

Why is an Rh control necessary?

To ensure a spontaneous agglutination that could yield a false positive is not present

The combination of screening cells used must contain antigenic expressions of

D, C, c, E, e, K, k, P1, M, N, S, s, Le^a, Le^b, Jk^a, Jk^b, Fy^a, Fy^b

Why do some labs not do the IS reading or room temperautre reading?

Antibodies found in these phases tend to be of no clincial signifiance

What is the risk of not reading after the 37 degree incubation?

Clinically signifianct antibodie in the Rh system might be missed

If CCC are negative, what are some possible causes?

Protein is present You forgot to add the reagent Inactive vial of AHG reagent

If the antibody screen is negative, what is the likely hood the crossmatch will be compatible?

Over 99%

What is CMV safe blood and when is it used?

Leukocyte reduced | Used in lung transplant patients

Patients undergoing a bone marrow transfusion require irradiation to prevent

graft-vs-host disease

Patients who experience febrile transfusions reactions may benefit from

leukoreduced blood

If Rh negative units are not available for a patient, you may give Rh+ and

RhoIg shot

what is an autologous donor?

A patient that donates for his/her own surgery

What is an allogenic donor?

Blood that comes from the general population

Order of transfusion donation

Autologous ABO/Rh compatible directed donor Allogenic

What percent of labs use IS crossmatch? What percent use IAT?

51% use immediate spin | 48% use IAT

When a serological crossmatch is performed, the donor blood used for testing must be taken from

an integrally attached segment of the donor unit

When ca you use the IS crossmatch?

When the antibody screen is non-reactive | No history of unexpected antibodies

If there is no reaction during IS crossmatch the unit is

compatible

What are some reasons for an incompatible (agglutinating) crossmatch?

Unit may be BO incompatible Rouleux Auto/alloantibodies Tube contamination

What are some reasons for an incompatible (agglutinating) cross match if ANTIBODY SCREEN IS NEGATIVE?

``` Alloantibody in recipient to low incedence antigen on donor RBCs Positive AHG on donor RBCs ABO error Contaminant Polyagglutinable donor RBC ```

What are some reasons for an incompatible (agglutinating) cross match if ANTIBODY SCREEN IS POSITIVE?

Alloantibody direct roward antigen on donor RBC | Contaminant

What are some reasons for an incompatible (agglutinating) cross match if ANTIBODY SCREEN IS POSITIVE and AUTOCONTROL POSITIVE?

Alloantibody present in recipient who has been transfused Auto/allo antibody in patient serum Rouleux

IAT may be performed on patients who demonstrate

clinically significant antibodies

Approximately 1/3 of potention hemolytic alloantibodies are not detected after

5 years

If you must transfuse incompatible blood in dire emergency and you cannot determine antibody ID you must

Medical director and physician decide Give "least incompatible" by AHG testing Watch patient

Since naturally occuring anti-A and anti-B are not demonstrated until 6 months, infants do not require

Reverse typing

If enough sample is not collected from an infant, an antibody screen may be performed on

maternal sample

If an antibody screen is negative, additional testing is not necessary for an infant if

Group O cells are used for transfusion

If an infant has a negative antibody screen, but recieves blood other than type O you must

run an intial crossmatch the include IAT

If an infant antibody screen is positive

you must identify and give antigen negative blood

In infants, it is important to crossmatch with blood that has a

stong antigenic expression

To transfuse, their must be two determinations of the recipients ABO group, and one determination must be

performed on a current sample

Ideally, 2 seperate ABO determinations are

performed by two different individuals

The type and screen is ___% effective in preventing the transfusion of incompatible blood.

99.99%

What is the frequency of an incompatible IAT crossmatch?

0.06-0.08%

What is the Maximum Surgical Blood Order?

list of an institution's surgical procedures and the corresponding blood usually available for a particular surgery. Represents a maximum blood order (not a minimum).

THE MSBOS allows transfusion services to monitor

The ration of crossmatches performed to transfusion givin (C/T) ration

What is a Blood Utilization Review?

transfusion committee performs review of transfusion practices. Audits in current time (prospective view), previous 12-24 hours time (concurrent audit), and days to months after transfusions (retrospective audit)

What is the definition of a Massive Transfusion?

the total blood volume of an individual has been replaces with donor blood within 24 hours

Massive transfusions diminish the purpose of

crossmatch

After a massive transfusion, you must continue to give previous antigen nagative blood because

a secondary response will be rapid for antibody production

In an emergency, if Type O- blood is given without compatibility testing, the unit must be labeled

clearly that pretransfusion testing was not complete at the time of issue