Clinical tests

Question 1

What is included in a full blood count?

Answer 1

Haemoglobin
Red cell count
Red cell indices
 - Mean corpuscular volume (MCV - red cell size)
 - Mean corpuscular haemoglobin (MCH)
 - (Mean corpuscular haemoglobin concentration MCHC)
Platelets
White cell count
 - Neutrophils
 - Lymphocytes
 - Monocytes
 - Eosinophils
 - Basophils

Question 2

What test can be used to differentiate between immune and non-immune haemolysis?

Answer 2

Direct Coombs test
aka DAGT (Direct Antiglobulin Test)

Question 3

What is LDH?

Answer 3

Lactate dehydrogenase

- like bilirubin, comes from prematurely destroyed RBCs)

Question 4

Give three tests done if a patient has a low haemoglobin

Answer 4

Ferritin
Reticulocyte count
B12 and folate

Question 5

What is erythropoietin?

Answer 5

hormone controlling red cell production
made in the kidney in response to hypoxia
can be given therapeutically to dialysis patients

Question 6

What is thrombopoietin?

Answer 6

hormone regulating platelet production
produced in the liver
agonists of thrombopoietin can be used therapeutically

Question 7

What forms of imaging can be useful in haematology?

Answer 7

CT angiogram e.g. to identify intracranial venous thrombosis
Plain film e.g. to see osteolytic lesions in skull in myeloma
CT scan e.g. to see pelvis erosion in myeloma

Question 8

List the major haematological tests other than FBC

Answer 8

Clotting times (indicate clotting factors)
Bleeding times (indicate platelets)
Chemical assays
 - iron (ferritin)
 - B12 and folate
Marrow aspirate and trephine biopsy
Lymph node biopsy

Question 9

Give two tests which assess clotting times

Answer 9

prothrombin time (PT)
activated partial thromboplastin time (APTT)

Question 10

What is the clinical difference between PT and APTT?

Answer 10

PT measures extrinsic (vitamin K dependant) clotting pathways which is useful for monitoring warfarin therapy

APTT measures intrinsic clotting pathways which is useful for monitoring heparin therapy

Question 11

How does the Direct Antiglobulin Test (DAGT) work?

Answer 11

detects antibody or complement on red cell membrane: reagent contains either
- anti-human IgG
- anti-complement
reagent binds to Ab/complement on red cell surface and causes agglutination in vitro, which implies an immune basis for haemolysis

Question 12

When is an indirect Coombs test used?

Answer 12

Blood transfusion preparation:
- cross-matching
- antibody screening ( ABO and Rh D )
Antenatal antibody screening

(aka indirect antiglobulin test or IAT)

Question 13

Give two probability-scoring tests which assess risk of VTE

Answer 13

Wells score

Geneva score

Question 14

What tests should be done if a VTW is suspected?

Answer 14

If low pre-test probability –> D-dimer

If high pre-test probability –> doppler compression USS, V/Q scan and/or CTPA

Question 15

When would a CTPA be done instead of a V/Q scan in cases of suspected PE?

Answer 15

If CXR is abnormal, go straight to CTPA

If V/Q is unavailable do a CTPA