Flashcard MLS IMMUNOHEMATOLOGY FINAL CLINICAL REVIEW | Quizlet

Which blood component contains the most factor VIII concentrate relative to the unit volume?

Cryoprecipitated AHF

A sample has reactions occurring at immediate spin and AHG in a panel that show varying strengths. There is no obvious pattern that matches a particular panel cell or single antigen profile and the auto-control was negative. Which of the following is most likely the cause?

An IgM and an IgG antibody

A rosette test to screen for fetal maternal hemorrhage should not be performed if the newborn has a weak-D antigen.

True: false negatives could occur

What should be done if all forward and reverse ABO results are negative?

Incubate at room temperature of 4˚ C to enhance weak expression.

If a pregnant female who was injected with RhIg antenatally has anti-D at delivery, routine antibody titration to determine the titer of the anti-D is considered to be a good practice.

False

A pregnant female has been injected with RhIg antenatally and has a positive antibody screen at delivery. If the antibody has been confirmed as anti-D alone and reacts only weakly (1+ in the IAT), the anti-D is definitely passive.

False. Only if the anti-D was strong could passive be ruled out

What is the most prudent step to follow to select units for cross-match after recipient antibodies have been identified?

Antigen type the patient cells and any donor cells to be cross-matched.

A group Oh Bombay individual's blood specimen can be differentiated from blood specimens of normal group O person's by:

Anti-H in serum

RhIg prophylaxis is typically given antenatally to Rh negative pregnant females without knowing the Rh type of the baby.

True

What type of packed red blood cells can be transfused to a group O patient?

Group O only

RhIg prevents anti-D production mainly by clearing antibody sensitized D-positive RBC's from maternal circulation

False

Phenotypes of offspring of type O parent and type A parent

O and A only

Which class of immunoglobulin is implicated in hemolytic disease of the fetus and newborn?

IgG

Which is the first marker (antigen or antibody) which will become positive after exposure to hepatitis B?

HBsAg

What action should be taken if a large clot is noticed in a red cell unit while the product is being prepared for release to the patient?

Do not issue the unit

At 28 weeks gestation an Rh-negative mother had a negative antibody screen and was injected with RhIg. Anti-D is detected in the mother's serum at the time of delivery. A panel is performed that excludes the presence of other antibodies. The most likely conclusion would be passive anti-D due to RhIg administration.

True

Reverse typing is done using known antisera to detect ABO antigens present on the patient red cells

False-

Reverse typing is done to detect patient antibodies in serum.

The most recent algorithm for HIV confirmatory testing in patients who are positive by HIV 1/2 antigen/antibody combination immunoassay is the

HIV1/HIV2 antibody differentiation immunoassay

The cause of the most severe life threatening hemolytic transfusion reaction is

Anti-A, Anti-B, and Anti-AB

A patient who received an autologous donation three weeks ago, can be reliably antigen typed

True. It is an autologous donation not allogeneic.

The most definite indication that a patient has been sensitized to a specific red cell antigen is

A positive post transfusion DAT in a patient with a previously negative DAT

A urticarial transfusion reaction is characterized by

Rash and Hives

Which test best correlates with the severity of hemolytic disease of a newborn?

Amniotic fluid bilirubin

FFP that has been thawed at 30-37˚C and maintained at 1-6˚C must be transfused within ______ hours after it has been thawed

24

IgG coated red cells are added to negative antiglobulin test to detect which source of error?

Failure to add Coombs serum

The temperature for maintaining red blood cell units during shipping is:

1-10˚C

Lectin from the seeds of Dolichos biflorus is a source of what?

Anti-A1

Why is RhIg administered within 72 hours of delivery or miscarriage to an Rh-negative mother if the newborn is found to be D-positive or weak D-positive?

Prevent fetal cells from initially sensitizing the mother

In immunohematology, an antithetical relationship exists between the M antigen and...

N

What condition is most frequently associated with anti-I?

Cold agglutinin disease

The accepted interval between blood donations is

8 weeks

Of the following blood group antibodies, which has been most frequently associated with severe cases of hemolytic disease of fetus and newborn?

Anti-K

Which enzymes can be enhanced by using enzyme panels during antibody identification in the blood bank?

Rh, Lewis, Kell

What should be the first step performed to resolve a case where all forward and reverse ABO typing results are negative on a patient?

Incubate at 22˚C

A delayed hemolytic transfusion reaction is most likely to be the result of which of the following antibodies?

Jk(a)

(Kidd antibodies are very dangerous and can cause severe delayed hemolytic transfusion reactions)

What is the most important first step to take when a patient is transfused with uncross-matched RBC's that turn out to be incompatible?

STOP THE TRANSFUSION IMMEDIATELY

What is the basic technique employed to detect antibodies with a commercial set of panel cells?

Indirect antiglobulin test

The prozone affect can be described by all of the following:

Results in a false negative reaction

The result of antibody excess

Dilution of antibody can help prevent its occurrence

The western blot assay was used as a confirmatory test for which disease?

Anti-HIV-1

IgM antibodies directed against red cells generally

React best at room temperature

Which transfusion reaction is most likely associated with transfused patients who lack IgA?

Anaphylaxis

The best way to thaw FFP is by

Placing the FFP in a 37˚C or lower water bath

If an R1r patient receives R2R2 blood what antibody will the patient develop?

Anti-E

What is the fundamental purpose of the full, pretransfusion cross match?

Detect antibodies in patient serum/plasma that react with donor red cells.

If a potential donor has been previously transfused with blood products, he must be deferred from blood donation for

1 year

What is the proper storage temperature for FFP?

-20˚C

The incidence of HDFN due to anti-D varies significantly according to race and ethnicity

True

Plasma exchange is the current treatment for which condition?

Thrombotic thrombocytopenia purpura (TTP)

Which of the following actions should take place if a donor experiences numbness in the mouth during an apheresis procedure?

Reduce the flow rate

What organism is MOST likely responsible for septic reactions associated with red blood cell transfusions?

Yersina entercolitica

What statements about anti-A1 are true?

It is a naturally occurring antibody

Anti-A1 and anti-A2 occur in 80 and 20% of the blood type A population respectively.

Dolichos biflorus has A1 specificity

Antibodies to __________ are the most frequent cause of febrile transfusion reactions

Granulocytes

The hh genotype gives rise to

Bombay phenotype

Antenatal RhIg is typically given at

28 weeks gestation

Which of the following blood components would be most appropriate for a 9-year-old girl with a low hemoglobin and low platelet count who has bleeding gums?

Platelet concentrate

Parents are AO and BO what are the possible offspring?

A, AB, B, and O

A former patient had an Anti-E four years ago but her antibody panel is now negative. Since she now needs blood for surgery, what should the blood bank do?

Cross match E-negative units

Why is it dangerous to transfuse a type O person with a unit of blood type A?

The patient's anti-A would destroy the donor cells with severe consequences to the patient.

What component is indicated for patients who receive directed donations from immediate family members to prevent transfusion-related graft vs. host disease.

Irradiated blood cells

When given during pregnancy RhIg may cross the placenta and sensitize fetal D-positive cells

True

The shelf life of whole blood collected CPDA-1 is

35 days

What is in the blood of an individual with the Bombay phenotype which will cause it to agglutinate with any non-Bombay individual's blood?

Anti-H

Which of Rh antigen is found in the highest frequency in Caucasians?

e

When AHG or coombs serum is used to demonstrate that red cells are antibody coated in vivo, the procedure is termed:

Direct technique

Transfusion related acute lung injury (TRALI) is a serious blood transfusion complication that can be characterized by:

Respiratory distress

Non-cardiogenic pulmonary edema

Mortality rate of 5-10%

False negative results at the IAT phase of the antibody screening test using tube method are usually caused by what?

Inadequate washing of the red cells

The DAT is usually used to detect

Antibodies coating red cells

Platelets should be stored at what temperature?

20-24˚C

An issued unit of blood may be returned to the blood bank inventory if it has not been outside a monitored refrigerator for longer than

30 minutes

In what way are the ABO serum antibodies unique among the blood group systems?

The antibodies are naturally occurring

The Rh nomenclature which uses the letters DCE is referred to as

Fisher-Race

An anti-D titer of 4 in a Rh-negative mother who has received RhIg indicates that the anti-D is passive and not immune.

False-

titer of 4 is consistent with both passive and immune

What percent of the overall population is Rh negative?

15%

If a patient has an antibody to a low frequency antigen like Kp(a) or Js(a), how would this impact the ability to find compatible blood and to identify the antibody?

Easy to find compatible blood but difficult to identify the antibody

Which physical exam result would cause a donor to be deferred?

Diastolic blood pressure of 110mm Hg (it should be no higher than 100)

In vivo vs. in vitro

In vivo is within the living

In vitro is within the glass

Which one of the following blood group systems may show a cell typing change during pregnancy?

Lewis-

Le(a) may disappear during pregnancy resulting in Le(a) antibodies.

Prozone effect may result in

False-negative results

A delayed hemolytic transfusion reaction occurring a week later is most likely caused by:

Kidd antibodies

In performing an AHG test it is important to completely wash the red cells in order to:

Avoid neutralization of the anti-human globulin serum

The ability to produce anti-D varies significantly among Rh negative individuals

True

A patient experiences a mild allergic reaction to transfusion, including urticaria, erythema, and itching. What is most likely the source of the allergen?

Plasma proteins

When performing an antibody panel, which antibody will be rendered inactive by enzyme treatment?

Fy(a)

Essential components of compatibility testing include:

Antibody screen on recipient's serum

Major cross match or computer cross match

ABO and Rh typing of recipient

Which antibody is detected primarily in the antiglobulin in the antiglobulin phase of the cross match?

Fy(a)

What is the first step a transfusionist should take when a transfusion reaction is suspected?

Stop transfusion but keep intravenous line open with saline

In HDN which of the following antibody-antigen interactions is occurring?

Maternal antibody against fetal antigen

What frequency should quality control testing be performed on each lot of anti-human globulin to be in compliance with the FDA's current good manufacturing practices requirements?

Each day of use

When a unit of packed RBCs is split using the open system, each half unit must be used within

24 hours

The term allogeneic blood is synonymous in meaning that the blood is

Donated by a donor for a recipient than the donor to use

Frequency equation:

100 x (neg frequency #1 x neg frequency #2)

Reconstituted deglycerolized red blood cells that have been prepared in an open system must be used within

24 hours

Following an infection with Mycoplasma pneumoniae a patient may demonstrate a strong cold agglutinin response against

Anti-I

Kernicterus due to high levels of unconjugated bilirubin can cause brain damage in new borns suffering from severe HDFN

True

Acceptable donor requirements

Temp: no greater than 99.5

Hematocrit: at least 38%

Blood pressure: no greater than 180 systolic and no greater than 100 diastolic

Pulse: regular (between 50 and 100 beats per minute)

Weight: Greater than 115lbs

What FFP ABO type would be suitable for transfusion to an AB negative person?

AB positive and AB negative only

How many international units of IgG anti-D are in 300 microgram vial of RhIg?

1500 (conversion is 5 for ever 1 microgram)

An exchange has been ordered for a low birth weight infant. The physician has ordered irradiated red blood cell products for this purpose. Why is it necessary to irradiate blood products for this patient?

To prevent transfusion-associated graft versus host disease

What procedure is used for the proper preparation of platelet concentrate from random whole-blood donors?

light spin followed by a hard spin

Which symptom of HDFN does phototherapy help prevent?

Kernicterus