MCQs Flashcards
What HB and red cell indices are indicative of severe iron deficiency?
HB = 6g/dl
MCV = 60
MCH = 15.5
What might a lack of intrinsic factor be due to?
Pernicious anaemia
What is used to fix a peripheral blood smear?
Methanol
What is the iron transport protein
Transferrin
What anticoagulant is used for cell counting analysis
EDTA
Ethylene-diamine-tetra acetic acid
What does polychromasia indicate?
The presence of immature red blood cells
Delta checking is a QC tool whereby:
Results obtained and compared to previous results
What is the most acute form of malaria caused by?
Plasmodium falciparum
What is thrombocytosis?
A platelet count above the reference range
How does platelet satellitism affect platelet count
May result in a falsely decreased platelet count on an autommated haematology counter
What might a platelet count of 25x10^5/L be associated with?
Platelet clumps on a blood smear
What is chronic myeloid leukaemia characterised by?
An increased number of immature myeloid cells
What is a major cause of a prolonged APTT?
Heparin therapy
What is the most common cause of neutrophilia?
Bacterial infection
What might cause a monocytosis?
Chronic infections such as TB
What is the most common cause of eosinophilia in Ireland?
Allergies or asthma -> rarely parasitic
How do we monitor the intrinsic pathway?
APTT assay
What is the inherited abnormality in the factor V molecule that renders it resistant to inactivation by protein C known as>
APCR
Activated protein C resistance
such as factor V leiden mutation
What can cause a low MCV and MCH
Iron deficiency
What causes microcytic, hypochromic rbcs?
Iron deficiency
When are sickle cells seen?
Haemoglobin S
What causes a vitamin B12 deficiency in most cases
Lack of intrinsic factor
What sample are full blood counts carried out on?
EDTA samples
What does Perls Prussian Blue stain detect?
Iron
What concentration of sodium citrate is used to measure ESR?
109 mmol/L
What are schistocytes
Fragmented red blood cells
What is thrombocytosis
A platelet count above the reference range
What platelet count indicates thrombocytopenia
<140 x 10^5/L
e.g. 20x10^5/L
What happens to platelets in chemotherapy
Platelet counts are reduced
What might cause a lymphocytosis
Viral infections
What test is used to confirm a diagnosis of Infectious Mononucleosis?
Monospot
What is the thromboplastin reagent used for?
PT assay
Fibrinogen is converted to fibrin by the action of which enzyme?
Thrombin
What is the recommended test for monitoring low molecular heparin?
anti-Xa assay
What might cause a lack of intrinsic factor
Pernicious anaemia
What is an erythroblast
A red cell precursor
What does a large number of sideroblasts and ringed sideroblasts in bone marrow stained with Prussian blue indicate
Sideroblastic anaemia
Is haptoglobin part of a haemolytic screen?
No
What are acanthocytes?
Red blood cells with irregularly distributed spicules
What is basophilic stippling?
RNA aggregates from broken down mitochrondria and ribosomes
At what platelet count is spontaneous bleeding most likely to occur
<10x10^5/L platelets
When is toxic granulation seen?
Bacterial infection
What is the infectious viral agent in infectious mono
Ebstein Barr Virus
What physiological protein’s anticoagulant effect is accelerated by heparin
Antithrombin
What does the ISI value of a thromboplastin reagent stand for?
An International Sensitivity Index
What is the units for haemoglobin
g/dL
What are hypersegmented neutrophils indicative of?
Megaloblastic anaemia
What is the formation of blood cells called?
Haemopoiesis
What is the staining solution used for manual reticulocyte counting?
Methylene Blue
What are Howell Jolly Bodies
Red cell inclusions made of DNA remnants
What is the role of activated platelets?
Activated platelets are involved in adhesion, aggregation and release reaction
What is anisocytosis
Variation in red blood cell size
What haematological disorders would you expect to see decreased platelet counts?
Any form of acute leukaemia
What is immunophenotyping the study of?
The study of antigen expression on cells
What are myelocytes
A form of immature neutrophil
What does ISI stand for
International Sensitivity Index
What clotting factor is deficient in Haemophilia A
Factor VIII
What factors are reduced when on Warfarin therapy
I, II, VII, X
(Vitamin K sensitive factors)
Protein C and S are also affected
What is needed to degrade fibrin strands to D-dimers
Plasmin
A patient has a Hb of 15g/dl and a haematocrit of 0.45L/L, what is the correct MCHC
MCHC = Hb/Hct
MCHC = 33.33
What treatment is carried out for the reversal of warfarin
Vitamin K -> IV
What parameter would be affected by a lipaemic sample?
Haemoglobin -> spectrophotometrically measured
What is the necessary pH for MGG stain?
6.85/6.90
How does EDTA work?
By chelating calcium ions
What are large reactive (atypical) lymphocytes with dispersed chromattin and irregular cytoplasmic membrane associated with?
Acute lymphoblastic leukaemia
How long does Warfarin take to manifest its anticoagulant response?
2 days
At what pH should the buffer be for a Giemsa stain to examine parasites?
pH 7.2
A patient has a Hct of 0.45L/L and an RBC count of 5x10^12/L, calculate the MCV
MCV = Hctx10/RBC count
MCV = 0.9
What is the definition of an acanthocyte?
abnormal red blood cells with spikes of different lengths and widths unevenly positioned on the cell surface
What is the staining solution used for manual reticulocyte counting?
New Methylene Blue stain
How does heparin exert its effects?
Heparin works via antithrombin, Heparin binds to and enhances the inhibitory activity of the plasma protein antithrombin against several serine proteases of the coagulation system, most importantly factors IIa (thrombin), Xa and IXa
Blast criteria for different leukaemias
AML > 20% blasts in the marrow or blood
MGG stain principle
- MGG stain at pH 6.8
- Two parts
o A basic/cationic dye which stains the nucleic acids e.g. azure B (any thiazin)
o A acid/anionic dye which stains the Hb and eosinophilic granules e.g. eosin
What stain is used for films (?) and bone marrow aspirated?
May Grunwald Giemsa @ pH 6.8
-> its a Romanowsky type stain
Sysmex flow cytometry measurement
The intensity of the forward scatter indicates the cell volume.
The side scatter provides information about the internal cell structure and its content, such as nucleus and granules.
The side fluorescence indicates the amount of nucleic acids present in the cell
