Haem

Question 1

What does an FBC test include?

Answer 1

Haemoglobin, White blood cells, platelets

used to detect anaemia, infection and clotting abnormalities.

Question 2

What does APTT measure?

Answer 2

The intrinsic and common coagulation pathways

prolonged in haemophilia and with heparin use.

Question 3

What does PT measure?

Answer 3

the extrinsic and common pathways

prolonged in liver disease, vitamin K deficiency, or warfarin use

Question 4

What is ESR used for?

Answer 4

A non specific marker for chronic inflammation or infection

elevated in autoimmune disease, infection or cancer

Question 5

How does ESR work?

Answer 5

ESR measures the rate RBCs settle in a vertical tube over one hour. In inflammation, fibrinogen and other acute-phase cause RBCs to stick together, making them settle faster - resulting a higher ESR.

Question 6

What causes a low Hb (anaemia) in FBC?

Answer 6

Blood loss, iron deficiency, chronic disease, B12/folate deficiency, haemolysis.

Question 7

What causes a raised WBC count?

Answer 7

Infection (esp bacterial), inflammation, leukaemia, steroid use.

Question 8

What causes a low platelet count?

Answer 8

Bone marrow failure, viral infection, autoimmune destruction, sepsis, medication

Question 9

Why are APTT and PT often both tested together?

Answer 9

They assess different parts of the coagulation cascade. Testing both help localise the problem

e.g. prolonged APTT and normal PT = intrinsic defect
both prolonged = liver disease or DIC

Question 10

Limitation of ESR

Answer 10

It is non specific and can be elevated in many conditions
- not a diagnostic on its own.

Influenced by age, sex and preganancy.