Haematology (Respiratory) Flashcards
What is haematology?
Study of blood, the blood-forming organs and blood diseases.
What is the difference between primary and secondary changes in blood?
Primary: changes in blood parameters could affect organ function. Secondary: changes in organ systems could impact on blood.
What should you look at/think about when interpreting lab values?
All parameters, normal ranges (age/gender differences), physiology, balance between production and destruction/loss.
What do developing red cells in the bone marrow need and why?
Vitamins B12 and folate for the nucleus to mature before its removal.
What are the 2 changes that can occur in blood cells?
Numbers (higher or lower, blood count) and appearances (morphology, blood film).
What count is often used as a surrogate for red cells?
Haemoglobin.
What is the MCV and what is it a useful starting point for?
Mean cellular volume of red blood cells. Determining the cause of anaemia in a patient.
What can microcytic (smaller), macrocytic (larger) or normocytic (normal) red blood cells tell us about anaemia?
Microcytic: due to iron deficiency e.g. chronic blood loss. Macrocytic: vitamin B12/folate deficiency (nuclear defects), alcohol excess, liver disease, hypothyroidism (membrane defect). Normocytic: acute blood loss or anaemia of chronic disease e.g. inflammation or infection.
What does increase in numbers of each leukocyte indicate?
Neutrophils: bacterial infections and during steroid use (redistributed in blood rather than true increase). Lymphocyte: common viral infections. Monocyte: atypical infections, cancers. Eosinophil: parasitic infections and allergies. Basophil: allergic reactions.
What is the naming rule for high white cell numbers?
For total white cell count and agranulocytes put cytosis on the end (e.g. leucocytosis), for granulocytes put philia on the end (e.g. eosinophilia).
What is platelet count used as a screening test for?
Primary haemostasis.
What is high platelets called and what does it mean?
Thrombocytosis - generally no alteration to haemostasis, caused by actute or chronic blood loss, inflammation or malignancies.
What is low platelets called and what does it mean?
Thrombocytopenia - may not be genuine as can form clumps in collection tube and confuse analyser. Due to liver disease, platelet consumption (autoimmune or in fibrin clot), trapping (enlarged spleen).
What can morphology of cells in a blood film tell us?
Target cells in liver disease (look like bullseyes), red cell fragments (valvular heart disease).
What can we assess about the components of plasma in a lab?
Assess coagulation proteins (secondary haemostasis) and plasma viscosity.
