Introduction to Haematology Flashcards
When might manual methods be used for FBE and blood films?
For samples that have unusual characteristics (e.g. ETDA can cause clumping of platelets mimicking thrombocytopaenia)
What is measured in an FBE?
Hb WCC (and differential assessing neutrophils, lymphocytes, monocytes, eosinophils, basophils) Platelets RCC PCV MCV MCH MCHC RDW
What is a blood film used for?
Explain FBE abnormalities by assessing morphology, colour, etc
Confirm white cell differential
What changes are seen on blood film that are indicative of oxidative haemolysis in anaemia?
Blister cells
Irregularly contracted cells
Polychromatic cells
What are haematinics? Give 3 examples
Vitamins and minerals important for normal haematopoiesis
E.g. iron, B12, folate
List 4 investigations to confirm haemolysis
Bilirubin
LDH
Haptoglobin
Reticulocyte count
List 2 enzyme deficiencies which may cause haemolysis
G6PD deficiency
PK deficiency
What investigations should be performed where a haemoglobinopathy is suspected?
FBE and film
High performance liquid chromatography (HPLC)
Hb electrophoresis
Genetic testing
List 4 causes of haemolysis related to abnormalities of the RBC membrane
Hereditary spherocytosis
Hereditary eliptocytosis
Hereditary stomatocytosis
Paroxysmal noctural haemoglobinuria (PNH)
What tests should be performed where a RBC membrane abnormality is suspected?
Flow cytometry assessing eosin-5-maleimide and FLAER
List 3 AI causes of haemolysis
AIHA
Cold haemagglutinin disease (CHAD)
Paroxysmal cold haemaglobinuria (PCH)
What tests should be performed where an AI cause of haemolysis is suspected?
Direct antiglobulin test (DAT)
Cold agglutinin screen
Donath-Landsteiner
List 4 causes of fragmentation haemolysis
Thrombotic thrombocytopaenic purpura/HUS
Cancer
DIC
Valve haemolysis
What tests should be performed where fragmentation haemolysis is suspected?
ADAMTS13
Coagulation profile
Renal function
List some indications for BM biopsy
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
TFPI
TF pathway inhibitor
APTT
Activated partial thromboplastin time
What does the APTT measure?
Factors in the intrinsic pathway (VIII, IX, XI, XII)
Factors in the common pathway (X, V, II/thrombin, fibrinogen)
What does the PT/INR measure?
Factors in the extrinsic pathway (VII)
Factors in the common pathway (X, V, II/thrombin, fibrinogen)
What is not measured by either the APTT or PT?
Factor XIII
What are the 3 major drawbacks of APTT and PT?
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)
What are the 3 main tests used for investigation of bleeding disorders?
Routine coags (APTT, PT/INR, fibrinogen)
Platelet count and morphology
Specialised tests
Give 4 examples of specialised tests used in the investigation of bleeding disorders
Factor assays
Inhibitor assays
Von Willebrand disease testing
Platelet aggregometry
What 3 tests should be ordered to investigate thrombotic tendency?
Assess for antiphospholipid Abs
Antithrombin, protein C and protein S levels
Genetic tests
What are the 2 ways to test for antiphospholipid Abs?
Directly (anticardiolipin and anti-B2GP1 Abs)
Indirectly via clotting assays (e.g. lupus anticoagulant)
What abnormalities are looked for in a genetic test investigating thrombotic tendency?
Factor V Leiden
Prothrombin gene mutation
What is the underlying disorder in Factor V Leiden?
Leiden variant of factor V cannot be inactivated by activated protein C
How is heparin monitored?
APTT
How is warfarin monitored?
INR
When and how should clexane be monitored?
In bleeding pt, pre-operatively, and in pt with renal impairment
Measured using anti-Xa assay
What are the 5 main anticoagulants used clinically?
Heparin Warfarin Clexane Dabigatran Riveroxaban
Dabigatran
Direct thrombin inhibitor
Riveroxaban
Xa inhibitor
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?
Factor deficiency
Perform assay of intrinsic factors and von Willebrand tests
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?
Factor inhibitor
Correct heparin dose or perform lupus anticoagulant assay
List 3 common causes of multiple factor deficiency
Reduced production due to vitamin K deficiency or liver disease
Increased consumption due to DIC
What is the most common single factor deficiency?
VIII
List 4 non-specific factor inhibitors
Heparin
Lupus anticoagulant
Paraprotein
What is the major Hb in adults?
a2B2
What is HbA2?
a2d2
What is HbF?
a2y2
What is the most common class of haemoglobinopathies?
Thalassaemias
What are thalassaemias?
Reduced production of a or B chain resulting in imbalance
What does HPLC do?
Measures proportions of different types of Hb
What blood group testing should be done prior to a transfusion?
ABO and D testing
Red cell Ab testing
How long does blood grouping take?
20-30 mins
MTP
Massive transfusion protocols (team approach involving treating clinicians, blood bank staff and transfusion specialist)
What 2 bodies should a transfusion-related adverse event be reported to?
Australian Red Cross Blood Service
Serious Transfusion Incident Reporting (STIR) scheme
