Question 1

Which condition is not considered prothrombotic?&#10;A)Graft versus host disease (GVHD)&#10;B)Heparin-induced thrombocytopenia (HIT)&#10;C)Hemolytic uremic syndrome (HUS)&#10;D)Thrombotic thrombocytopenia purpura (TTP)

Accepted Answer

Graft versus host disease (GVHD) is not considered prothrombotic. It is a complication that can occur after bone marrow transplantation where the donor's immune cells attack the recipient's cells. While patients with GVHD can have bleeding and clotting problems, the underlying mechanism is not related to abnormal coagulation. On the other hand, HIT, HUS and TTP are all prothrombotic conditions that can cause blood clots to form in the circulation.

Question 2

Which of the following mechanisms results in immune-mediated platelet refractoriness?&#10;A)Alloimmunization&#10;B)Consumption&#10;C)Sequestration&#10;D)Thrombosis

Accepted Answer

Alloimmunization can occur when a patient receives multiple transfusions of platelets from different donors, leading to the development of alloantibodies against the donors' platelets. These alloantibodies can then cause platelet refractoriness by binding to and destroying transfused platelets before they can function in the recipient's circulation.

Question 3

Platelet refractoriness can be indicated by an immediate post-transfusion corrected count increment (CCI)of less than&#10;A)5,000 on at least one occasion&#10;B)5,000 on at least two occasions&#10;C)7,500 on at least one occasion&#10;D)7,500 on at least two occasions

Accepted Answer

Platelet refractoriness is indicated by a CCI of less than 5,000 on at least two occasions. A single low CCI may be due to factors such as rapid platelet clearance or incorrect timing of the post-transfusion count. Therefore, two low CCIs are required for a more accurate diagnosis of platelet refractoriness. Option A and Option C are incorrect as they have lower CCI thresholds and may be accounted for by other factors besides true platelet refractoriness. Option D is also incorrect as it has a higher CCI threshold, which may miss cases of partial platelet refractoriness.

Question 4

What are the three most common human platelet antigen (HPA)antibodies implicated in platelet refractoriness?&#10;A)Anti-HPA-1a,anti-HPA-2a,anti-HPA-5a&#10;B)Anti-HPA-1b,anti-HPA-2a,anti-HPA-5a&#10;C)Anti-HPA-1b,anti-HPA-2b,anti-HPA-5a&#10;D)Anti-HPA-1b,anti-HPA-2b,anti-HPA-5b

Accepted Answer

The answer of What are the three most common human...

Question 5

An advantage of platelet crossmatching is&#10;A)the immediate availability of compatible units&#10;B)the fact that it decreases the overall transfusion time&#10;C)that platelets have a shelf-life of 5 days&#10;D)that crossmatched platelets perform better than high-grade HLA-matched products

Accepted Answer

Platelet crossmatching allows for the immediate availability of compatible units, which is particularly important in emergency situations where time is critical. This eliminates the wait time that would be required for other methods such as high-grade HLA-matched products. Platelets have a shelf-life of only 5 days, so the timeliness of transfusions is crucial. While crossmatched platelets may not necessarily perform better than high-grade HLA-matched products, their immediate availability makes them a valuable option in certain situations.

Question 6

Platelet transfusion is usually required to treat which of the following conditions?&#10;A)Heparin-induced thrombocytopenia (HIT)&#10;B)Idiopathic thrombocytopenia purpura (ITP)&#10;C)Neonatal alloimmune thrombocytopenia (NAIT)&#10;D)Post-transfusion purpura (PTP)

Accepted Answer

Neonatal alloimmune thrombocytopenia (NAIT) is a condition where the mother's immune system attacks the platelets of the fetus or newborn, leading to severe thrombocytopenia (low platelet count). Platelet transfusions are often required to treat or prevent bleeding in affected infants. In contrast, platelet transfusions are generally avoided in conditions like Heparin-induced thrombocytopenia (HIT), Idiopathic thrombocytopenia purpura (ITP), and Post-transfusion purpura (PTP) due to the risk of exacerbating the underlying immune-mediated platelet destruction or contributing to thrombosis, especially in HIT.

Question 7

Currently how many human platelet antigens (HPAs)have been identified?&#10;A)12&#10;B)18&#10;C)24&#10;D)32

Accepted Answer

As of my last update in 2023, 24 human platelet antigens (HPAs) have been identified. These antigens are important for understanding various platelet-related disorders and for ensuring compatibility in transfusions and transplants.

Question 8

Which antibody is the most common cause of neonatal alloimmune thrombocytopenia?&#10;A)Anti-HLA-DQ1&#10;B)Anti-HLA-Dq&#178;&#10;C)Anti-HPA-1a&#10;D)Anti-HPA-1b

Accepted Answer

Anti-HPA-1a is the most common cause of neonatal alloimmune thrombocytopenia, which occurs when the mother's immune system produces antibodies against platelet antigens inherited from the father that are not present in the mother. This can cause destruction of the fetal platelets and lead to bleeding in the neonate. The other antibody options listed (A, B, and D) are not typically associated with neonatal alloimmune thrombocytopenia.

Question 9

All of the following are factors that influence alloimmunization except&#10;A)Antigen dose&#10;B)Consumption rate&#10;C)Immune status&#10;D)Prior exposure

Accepted Answer

Consumption rate does not influence alloimmunization. The other factors such as antigen dose, immune status, and prior exposure can impact the development of an immune response and the likelihood of alloimmunization.

Question 10

What is the first step to take when platelet refractoriness is suspected in a patient?&#10;A)Confirm the response to the transfusion&#10;B)Obtain a complete and accurate history&#10;C)Screen the patient for HLA and/or HPA antibodies&#10;D)Transfuse ABO-identical platelets

Accepted Answer

The first step is to confirm the response to the transfusion by measuring the post-transfusion platelet count to determine if refractoriness is present.

Question 11

Which is the most common causative agent of drug-induced immune thrombocytopenia today?&#10;A)Amphotericin B&#10;B)Cephalexin&#10;C)Heparin&#10;D)Quinine

Accepted Answer

The answer of Which is the most common causative agent...

Question 12

Platelets removed from circulation and stored by the spleen best describes which of the following terms?&#10;A)Platelet alloimmunization&#10;B)Platelet consumption&#10;C)Platelet refractoriness&#10;D)Platelet sequestration

Accepted Answer

The answer of Platelets removed from circulation and stored by...

Question 13

Which patients are at the highest risk for developing platelet refractoriness?&#10;A)Anaesthetized surgical&#10;B)Bleeding trauma&#10;C)Chronically transfused oncology&#10;D)Multiparous obstetrical

Accepted Answer

The answer of Which patients are at the highest risk...

Question 14

The antibodies most commonly implicated in immune platelet refractoriness are directed against which group of antigens?&#10;A)ABO&#10;B)HLA&#10;C)HPA&#10;D)Rh

Accepted Answer

The answer of The antibodies most commonly implicated in immune...

Question 15

Transfusion of which blood component is most often associated with post-transfusion purpura (PTP)?&#10;A)Plasma&#10;B)Platelets&#10;C)Red blood cells&#10;D)White blood cells (granulocytes)

Accepted Answer

The answer of Transfusion of which blood component is most...

Question 16

Platelet counts should ideally be tested how long after a platelet transfusion?&#10;A)10-15 minutes and 12-14 hours&#10;B)15-30 minutes and 18-20 hours&#10;C)15-60 minutes and 20-24 hours&#10;D)1 hour,24 hours,and 48 hours

Accepted Answer

The answer of Platelet counts should ideally be tested how...

Question 17

If the information necessary to calculate corrected count increment (CCI)or post-transfusion platelet recovery (PPR)is not available,a rough estimate of _________ increment per one unit of platelet concentrate transfused in an average adult patient can be used.

A)500/µL
B)1,000/µL
C)2,000/µL
D)5,000/µL

Accepted Answer

The answer of If the information necessary to calculate corrected...

Question 18

What is the match called when one human leukocyte antigen (HLA)is mismatched?&#10;A)A&#10;B)BU&#10;C)C&#10;D)D

Accepted Answer

The answer of What is the match called when one...

Question 19

Accumulation of ultra-large multimers of von WilLe&#7495;rand factor causes which of the following conditions?&#10;A)Disseminated intravascular coagulation (DIC)&#10;B)Graft versus host disease (GVHD)&#10;C)Heparin-induced thrombocytopenia (HIT)&#10;D)Thrombotic thrombocytopenia purpura (TTP)

Accepted Answer

The answer of Accumulation of ultra-large multimers of von WilLe&#7495;rand...

Question 20

What is an identical human leukocyte antigen (HLA)match called?&#10;A)A&#10;B)BU&#10;C)C&#10;D)D

Accepted Answer

The answer of What is an identical human leukocyte antigen...

Deck 16: Platelet Refractory Patients