Haematology II Flashcards
Which of the following is true regarding the prothrombin time (PT)?
(Please select 1 option)
Assesses the intrinsic pathway of the blood coagulation cascade
Is increased with low molecular weight heparin
Is increased with warfarin
Is not prolonged in patients with fat malabsorption
May be restored to normal by the administration of protamine
Is increased with warfarin
It assesses the extrinsic pathway and therefore is prolonged with abnormalities of factors VII, X, V, or II.
The normal prothrombin time is 16-18s and is prolonged in patients with fat absorption.
The coumarin warfarin interferes with vitamin K metabolism, which inhibits the ã-carboxylation of factors II, VII, IX, and X and thus prolongs the prothrombin time.
Heparin has an immediate effect on coagulation by potentiation of the formation of irreversible complexes between antithrombin and activated serine protease coagulation factors and thus has minimal effects on the prothrombin time.
Low molecular weight heparin specifically acts on factor Xa and thus is not monitored either through activated partial thromboplastin time (APTT) or PT.
Vitamin K restores a normal prothrombin time and is used therapeutically if the PT is prolonged or the INR is very high.
Which one of the following is true of blood coagulation?
(Please select 1 option)
Addition of vitamin K to freshly drawn blood delays clotting
Heparin inhibits blood coagulation through its interference with vitamin K metabolism in the liver
Platelets are essential for blood clot
Thrombin converts fibrin to fibrinogen
Vitamin K is required for the production of factors III, VI, XI and XII
Platelets are essential for blood clot
Regarding blood coagulation:
Heparin increases the activity of anti-thrombin III which inhibits the clotting cascade
Vitamin K is used in liver to produce clotting factors and on its own has no anti-coagulation effect
Thrombin is important in the clotting cascade by releasing fibrin from fibrinogen
Platelets are essential for clotting factors II, VII, IX and X are produced in liver with vitamin K.
Which of the following is true of endotoxins?
(Please select 1 option)
Are involved in botulism
Can often survive autoclaving
Elicit an antibody response which may protect the host from future attack
Is found in the vesicle of bacterial cytoplasm
Is produced mainly by Gram positive bacteria
Can often survive autoclaving
Endotoxins:
Are lipopolysaccharides derived from the cell wall of Gram negative bacteria
Are heat stable (compare with exotoxin)
Are non-antigenic (compare with exotoxin)
Cause septicaemia and fever
Activate the alternative complement pathway.
Which of the following is correct regarding blood group antibodies?:
(Please select 1 option)
Anti-A and anti-B antibodies are usually IgM
Anti-A and anti-B are warm antibodies
Anti-D is a cold antibody
IgM antibodies are capable of transplacental passage
The rhesus antibody, anti-D is an IgM antibody
Anti-A and anti-B antibodies are usually IgM
Anti-A and anti-B are naturally occurring antibodies and are usually IgM. They react optimally at cold temperatures (4°C) and although reactive at body temperature they are called cold antibodies.
Immune antibodies like the rhesus antibody, anti-D, are commonly IgG. They react optimally at 37°C and are called warm antibodies.
Only IgG antibodies are capable of transplacental passage to the fetus.
A patient on the ward receiving a blood transfusion after hip replacement surgery is noted to have rigours.
On examination his temperature is 39°C ( baseline 36.5°C ). He also complains of abdominal pain and his blood pressure is 90 /55 mmHg (baseline 126/84 mmHg).
Which of the following is the next step in management of this patient?
(Please select 1 option)
Continue 10 min observations till completion of transfusion
Give the patient 1 g of paracetamol and continue transfusion
Give the patient chlorpheniramine 10 mg and paracetamol 1 g while slowing the rate of transfusion
Notify blood bank to recheck cross match
Stop the transfusion immediately and commence IV fluids
Stop the transfusion immediately and commence IV fluids This is the correct answerThis is the correct answer
This patient should be suspected to have an acute haemolytic transfusion reaction given the more than 2°C rise in temperature, abdominal pain and hypotension.
The transfusion should be stopped immediately, the set taken down and saline infusion commenced.
The blood bank needs to be notified and a sample may need to be collected but this is not the first priority.
If a severe haemolytic transfusion reaction is suspected the transfusion should not be continued (hence the remaining answer options are incorrect).
Which of the following statements is true about the storage conditions and shelf life of blood products?
(Please select 1 option)
Fresh frozen plasma is stored at −30°C for 12 months IncorrectIncorrect answer selected
Fresh frozen plasma is stored at −30°C for up to 24 months This is the correct answerThis is the correct answer
Packed red cells are stored at 4°C for up to 25 days
Platelets are stored at 4°C for up to 5 days
Platelets stored for 5 days at 22°C in a temperature controlled fridge
Fresh frozen plasma can be stored up to 24 months at −30°C.
Red cells are stored at 4°C for up to 35 days and platelets at 22°C for 5 days on a platelet shaker/agitator.
Which of the following is true about manufacture of pooled plasma derivatives?
(Please select 1 option)
Pooled plasma is often sourced from within the UK
The end product is a freeze dried product
The process does not involve any viral inactivation steps
These are usually manufactured from 10 donors at a time
These products have a short half life typically days
The end product is a freeze dried product
The plasma derivatives (such as Factor VIII) are prepared from several thousand plasma donations, typically 20,000 or 5000kg of plasma at a time. Pooled plasma has been sourced from outside UK since 1999 to avoid vCJD risks. The process involves several chemical steps including ethanol extraction, chromatography and viral inactivation steps, which results in a freeze dried product. These products have a long shelf life of several months to years.
Which of the following infusion times would be appropriate during the transfusion of a blood product in a stable patient?
(Please select 1 option)
A packed cell transfusion should be given over 20 minutes
A packed cell transfusion should be given over 90 minutes
A platelet transfusion should be given over 60 minutes
A platelet transfusion should be given over 90 minutes
A platelet transfusion should be given over 120 minutes
A packed cell transfusion should be given over 90 minutes
In a stable patient red cell packs may be transfused over 90-120 minutes while a platelet transfusion should not take more than 20-30 minutes.
Rapid infusion of red cells or fresh frozen plasma may be required in acutely bleeding patient but not in this patient who is stable.
What is the minimum dataset required for identifying a patient and a sample for purpose of a blood transfusion request?
(Please select 1 option)
Full name and gender
Full name, gender and patient identity number
Full name, gender, address and patient identity number
Full name, gender, date of birth, address and patient identity number
Full name, gender, previous blood grouping details, address and patient identity number
Full name, gender, date of birth, address and patient identity number
Given that maximum errors and near misses occur because of mislabelling or mistaken identity of patient or the sample a minimum data set is prescribed for transfusion requests.
This involves recording the full name, gender, date of birth, address (in some areas) and patient identity number. Previous blood grouping details are not required and missing elements of this minimum dataset are not acceptable in the transfusion service.
For which of the following patients would a gamma irradiated blood product be recommended?
(Please select 1 option)
16-year-old thalassaemic receiving regular transfusions
19-year-old nulliparous female after a road traffic accident
37-year-old patient with Hodgkin’s lymphoma receiving chemotherapy
42-year-old lady receiving adjuvant hormonal therapy for breast cancer post radical mastectomy
Post operatively for carcinoma of the colon in a 50-year-old male
37-year-old patient with Hodgkin’s lymphoma receiving chemotherapy
The most common indications for irradiated blood products include those at risk of transfusion associated graft versus host disease such as:
Neonates
Those receiving purine analogue based chemotherapy
Hodgkin’s lymphoma
Immunodeficiency states
Post bone marrow transplants
The other scenarious described here do not necessarily represent an immunosupressed state in the list of conditions eligible for an irradiated blood product.
A pre-transfusion sample shows that a patient has blood group O.
This means that which of the following is true?
(Please select 1 option)
The red cells have A/B antigen but no antibodies in the plasma
The red cells have absent A/B antigen and plasma has anti A and anti B antibodies
The red cells have antigen A and plasma has anti B antibodies
The red cells have antigen B and plasma has A antibodies
The red cells may have any antigen but plasma has anti A and anti B antibodies
The red cells have absent A/B antigen and plasma has anti A and anti B antibodies
The answer options represent the following blood groups:
Blood Group O: The red cells have absent A/B antigen and plasma has anti A and anti B antibodies
Blood Group AB: The red cells have A /B antigen but no antibodies in the plasma
Blood Group A: The red cells have antigen A and plasma has anti B antibodies
Blood Group B: The red cells have antigen B and plasma has A antibodies
The remaining incorrect answer option does not represent any blood group
The risk of a viral infection transmitted via a transfusion is widely variable.
In the UK, the risk of transmission of hepatitis B would be best described as which of the following?
(Please select 1 option)
Slightly less than 0.01 per million donations
0.05 per million donations
0.2 per million donations
1 per million donations
Slightly more than 2 per million donations
Slightly more than 2 per million donations This is the correct answerThis is the correct answer
The common viral infections considered in the infective risks of a blood transfusion are hepatitis B, hepatitis C and HIV.
The risks are variable depending on the source of donation and the type of testing employed but generally in the United Kingdom the risks for hepatitis B are in the order of 2.2/ million donations while those for HIV and hepatitis C are 0.2 and 0.05/ million donations.
A broad knowledge of the risks may be required while consenting a patient for blood transfusion.
Which of the following is the blood product with the highest risk of transmission of a bacterial infection related to transfusion? (Please select 1 option) Cryoprecipitate Fresh frozen plasma Factor VIII concentrates Packed red cells Platelets
Platelets This is the correct answerThis is the correct answer
Since platelets are stored at room temperature (22°C), the risk of bacterial contamination is highest in this blood product.
In contrast, packed red cells are stored at an average of 4°C, while fresh frozen plasma as well as cryoprecipitate are stored at -20°C.
Factor VIII concentrates are heat inactivated freeze dried products with a minimal risk of bacterial contamination.
Which of the following potential blood donors would be excluded from donating whole blood or plasma?
(Please select 1 option)
A 27-year-old man who has had a tattoo on his arm for the last ten years
A 32-year-old lady whose sister was diagnosed with Creutzfeld-Jakob disease 3 years ago
A 38-year-old lady who underwent acupuncture for leg pain 5 months ago with a registered health professional
A 42-year-old man with a history of hepatitis when he was aged 18 years
A 56-year-old man who had a course of antibiotics for an upper respiratory tract infection which was completed 4 weeks ago
A 32-year-old lady whose sister was diagnosed with Creutzfeld-Jakob disease 3 years ago
Any potential donor whose immediate family member (parent or sibling) has had Creutzfeld-Jakob disease needs to be excluded from blood donation.
All other options cannot be excluded on the basis of the current blood donation guidelines (National blood service UK).
Hepatitis or jaundice would be an exclusion only if it occurred in the last 12 months.
Acupuncture in the last four months (unless performed by a registered professional) or body piercing /tattoos in the last six months would also be an exclusion.
Any infection in the preceding two weeks or a course of antibiotics within the last seven days would be considered an exclusion.
A 56-year-old man is being reviewed for an elective cholecystectomy in the pre-op clinic.
He has no co-morbidities apart from 2 attacks of cholecytitis in the last 12 months. He has never received a blood transfusion in the past.
What should the request for the blood bank include?
(Please select 1 option)
Cross match for 3 units only
Group and Save as well as cross match
Group and Save, direct Coombs’ Test and a cross match for 2 units
Group and Save, direct Coombs’ Test and a cross match for 3 units
Group and Save only
Group and Save only This is the correct answerThis is the correct answer
A ‘group and save’ is adequate for elective surgeries and is standard practise in most modern blood banks. This will involve blood grouping and its confirmation as well as an antibody screen.
Other options include crossmatch and a direct Coombs’ Test (DAT) which are often done only if the antibody screen test is positive. These are not routinely done for elective surgery unless the patient has had a recent blood transfusion or a history of previous known red cell antibodies.
