Introduction to Haematology

Question 1

When might manual methods be used for FBE and blood films?

Answer 1

For samples that have unusual characteristics (e.g. ETDA can cause clumping of platelets mimicking thrombocytopaenia)

Question 2

What is measured in an FBE?

Answer 2

Hb
WCC (and differential assessing neutrophils, lymphocytes, monocytes, eosinophils, basophils)
Platelets
RCC
PCV
MCV
MCH
MCHC
RDW

Question 3

What is a blood film used for?

Answer 3

Explain FBE abnormalities by assessing morphology, colour, etc
Confirm white cell differential

Question 4

What changes are seen on blood film that are indicative of oxidative haemolysis in anaemia?

Answer 4

Blister cells
Irregularly contracted cells
Polychromatic cells

Question 5

What are haematinics? Give 3 examples

Answer 5

Vitamins and minerals important for normal haematopoiesis

E.g. iron, B12, folate

Question 6

List 4 investigations to confirm haemolysis

Answer 6

Bilirubin
LDH
Haptoglobin
Reticulocyte count

Question 7

List 2 enzyme deficiencies which may cause haemolysis

Answer 7

G6PD deficiency

PK deficiency

Question 8

What investigations should be performed where a haemoglobinopathy is suspected?

Answer 8

FBE and film
High performance liquid chromatography (HPLC)
Hb electrophoresis
Genetic testing

Question 9

List 4 causes of haemolysis related to abnormalities of the RBC membrane

Answer 9

Hereditary spherocytosis
Hereditary eliptocytosis
Hereditary stomatocytosis
Paroxysmal noctural haemoglobinuria (PNH)

Question 10

What tests should be performed where a RBC membrane abnormality is suspected?

Answer 10

Flow cytometry assessing eosin-5-maleimide and FLAER

Question 11

List 3 AI causes of haemolysis

Answer 11

AIHA
Cold haemagglutinin disease (CHAD)
Paroxysmal cold haemaglobinuria (PCH)

Question 12

What tests should be performed where an AI cause of haemolysis is suspected?

Answer 12

Direct antiglobulin test (DAT)
Cold agglutinin screen
Donath-Landsteiner

Question 13

List 4 causes of fragmentation haemolysis

Answer 13

Thrombotic thrombocytopaenic purpura/HUS
Cancer
DIC
Valve haemolysis

Question 14

What tests should be performed where fragmentation haemolysis is suspected?

Answer 14

ADAMTS13
Coagulation profile
Renal function

Question 15

List some indications for BM biopsy

Answer 15

Investigation of unexplained anaemia, abnormal RBC indices, cytopaenias, cytoses
Investigation of abnormal blood smear suggestive of BM pathology
Diagnosis, staging, follow-up for cancers involving BM, or of suspected mets
Investigation of PUO
Investigation of lipid/glycogen storage disorders
Evaluation of potential transplant donors
Evaluation of iron stores

Question 16

TFPI

Answer 16

TF pathway inhibitor

Question 17

APTT

Answer 17

Activated partial thromboplastin time

Question 18

What does the APTT measure?

Answer 18

Factors in the intrinsic pathway (VIII, IX, XI, XII)

Factors in the common pathway (X, V, II/thrombin, fibrinogen)

Question 19

What does the PT/INR measure?

Answer 19

Factors in the extrinsic pathway (VII)

Factors in the common pathway (X, V, II/thrombin, fibrinogen)

Question 20

What is not measured by either the APTT or PT?

Answer 20

Factor XIII

Question 21

What are the 3 major drawbacks of APTT and PT?

Answer 21

Don’t measure anticoagulant/haemolytic pathway
Amount required for normal test may not be sufficient for normal haemostasis
Results are very sensitive to sample variation (factors very labile)

Question 22

What are the 3 main tests used for investigation of bleeding disorders?

Answer 22

Routine coags (APTT, PT/INR, fibrinogen)
Platelet count and morphology
Specialised tests

Question 23

Give 4 examples of specialised tests used in the investigation of bleeding disorders

Answer 23

Factor assays
Inhibitor assays
Von Willebrand disease testing
Platelet aggregometry

Question 24

What 3 tests should be ordered to investigate thrombotic tendency?

Answer 24

Assess for antiphospholipid Abs
Antithrombin, protein C and protein S levels
Genetic tests

Question 25

What are the 2 ways to test for antiphospholipid Abs?

Answer 25

Directly (anticardiolipin and anti-B2GP1 Abs) | Indirectly via clotting assays (e.g. lupus anticoagulant)

Question 26

What abnormalities are looked for in a genetic test investigating thrombotic tendency?

Answer 26

Factor V Leiden | Prothrombin gene mutation

Question 27

What is the underlying disorder in Factor V Leiden?

Answer 27

Leiden variant of factor V cannot be inactivated by activated protein C

Question 28

How is heparin monitored?

Answer 28

APTT

Question 29

How is warfarin monitored?

Answer 29

INR

Question 30

When and how should clexane be monitored?

Answer 30

In bleeding pt, pre-operatively, and in pt with renal impairment Measured using anti-Xa assay

Question 31

What are the 5 main anticoagulants used clinically?

Answer 31

``` Heparin Warfarin Clexane Dabigatran Riveroxaban ```

Question 32

Dabigatran

Answer 32

Direct thrombin inhibitor

Question 33

Riveroxaban

Answer 33

Xa inhibitor

Question 34

If a prolonged APTT is corrected with a 1:1 mix with normal plasma, what does this indicate about the cause of the abnormality? What further tests should be done in this case?

Answer 34

Factor deficiency | Perform assay of intrinsic factors and von Willebrand tests

Question 35

If a prolonged APTT is not corrected with a 1:1 mix with normal plasma, what does this indicate about the cause of the abnormality? What further actions should be taken in this case?

Answer 35

Factor inhibitor | Correct heparin dose or perform lupus anticoagulant assay

Question 36

List 3 common causes of multiple factor deficiency

Answer 36

Reduced production due to vitamin K deficiency or liver disease Increased consumption due to DIC

Question 37

What is the most common single factor deficiency?

Answer 37

VIII

Question 38

List 4 non-specific factor inhibitors

Answer 38

Heparin Lupus anticoagulant Paraprotein

Question 39

What is the major Hb in adults?

Answer 39

a2B2

Question 40

What is HbA2?

Answer 40

a2d2

Question 41

What is HbF?

Answer 41

a2y2

Question 42

What is the most common class of haemoglobinopathies?

Answer 42

Thalassaemias

Question 43

What are thalassaemias?

Answer 43

Reduced production of a or B chain resulting in imbalance

Question 44

What does HPLC do?

Answer 44

Measures proportions of different types of Hb

Question 45

What blood group testing should be done prior to a transfusion?

Answer 45

ABO and D testing | Red cell Ab testing

Question 46

How long does blood grouping take?

Answer 46

20-30 mins

Question 47

MTP

Answer 47

Massive transfusion protocols (team approach involving treating clinicians, blood bank staff and transfusion specialist)

Question 48

What 2 bodies should a transfusion-related adverse event be reported to?

Answer 48

Australian Red Cross Blood Service | Serious Transfusion Incident Reporting (STIR) scheme