Data interpretation: Full Blood Count

Question 1

What 2 things should you confirm before interpreting the FBC?

Answer 1

Patient details

Date and time of FBC

Question 2

On the FBC, what are the first 3 results you should look at and why?

Answer 2

Haemoglobin concentration

RBC count

Haematocrit

These help to identify anaemia or polycythemia

Question 3

If a FBC shows an abnormally low haemoglobin concentration and RBC count, what finding causes this?

Answer 3

Anaemia

Question 4

In FBC interpretation, what should you identify next if the patient has anaemia, and how?

Answer 4

Is the anaemia macrocytic, normocytic or microcytic

Look at MCV result

Question 5

What is the Mean Corpuscular Volume (MCV), and what does it indicate in FBC interpretation?

Answer 5

Average volume of red blood cell

Normal MCV: 80-100, so RBCs are normocytic

High MCV: Over 100, so RBCs are macrocytic

Low MCV: Less than 80, so RBCs are microcytic

Question 6

After identifying a microcytic anaemia, what are the possible causes? (TRAILS)

Answer 6

Thalassemia

Rheumatoid arthritis

Anaemia of chronic disease

Iron-deficiency anaemia

Lead poisoning

Sideroblastic anaemia

Question 7

After identifying a macrocytic anaemia, what are the possible causes? (ABCDEF)

Answer 7

Alcohol or liver disease

B12 deficiency

Complementary reticulocytosis (due to haemolytic anaemia)

Dysplasia

Endocrine

Folate deficiency, foetus aka pregnancy

Question 8

After identifying a normocytic anaemia, what are the possible causes? (ABCD)

Answer 8

Acute blood loss

Bone marrow failure

Chronic disease

Destruction aka haemolysis

Question 9

In FBC interpretation, what does haematocrit mean and what is the normal range?

Answer 9

Volume percentage of RBCs in blood

Normal range for women: 37-45%

Normal range for men: 40-50%

Question 10

In FBC interpretation, which 2 conditions are indicated by abnormally high haematocrit?

Answer 10

True polycythemia

Apparent polycythemia

Question 11

In FBC interpretation, which 3 readings distinguish between true and apparent polycythemia?

Answer 11

True polycythemia: Increased haematocrit, increased haemoglobin concentration, increased RBC count

Apparent polycythemia: Increased haematocrit concentration, increased haemoglobin, normal RBC count

Question 12

What is the underlying cause of true and apparent polycythemia, and which FBC result indicates this?

Answer 12

Hb conc and haematocrit are elevated so look at RBC count

True polycythemia: Increased RBC production, which increases RBC count

Apparent polycythemia: Decreases plasma volume but there is no more RBC production, which causes normal RBC count

Question 13

What are the 2 main conditions which cause true polycythemia?

Answer 13

Essential polycythemia

Secondary polycythemia

Question 14

Give 3 causes of apparent polycythemia?

Answer 14

Overweight

Dehydration: Alcohol intake, diuretics

Smoking

Question 15

In FBC interpretation, what should you look at after RBC readings?

Answer 15

WBC counts

Neutrophils

Eosinophils

Basophils

Question 16

What are the causes of neutropenia? (Panic with 3 eyes)

Answer 16

P: Post-infection: Sepsis

A: Autoimmune conditions or drugs

N: Neoplasms: Lymphoproliferative or myelodysplastic

I: Infection: HIV, viral hepatitis

I: Idiopathic

I: Insufficiency eg. B12, folate

C: Consumption: Hypersplenism

Question 17

What are the causes of neutrophilia?

Answer 17

Infection & inflammation

Pregnancy

Smoking

Stress

CML

Drugs

Question 18

What are the causes of lymphocytosis?

Answer 18

CLL

Lymphoma

Acute viral or bacterial infections

Hyposplenism

Question 19

Compare the FBC results of CLL and CML?

Answer 19

CLL: Lymphocytosis

CML: Granulocytosis: Neutrophilia, basophilia, eosinophilia

Question 20

What are the causes of eosinophilia? (ALLERGIC)

Answer 20

A: Adrenal insufficiency (Addison’s disease)

L: Lymphoma (Hodgkin’s)

L: L-tryptophan deficiency

E: Eczema and atopic diseases

R: Respiratory (asthma, aspergillosis)

G: Gastroenteritis

I: Infection (parasite, fungal)

C: Collagen vascular syndromes (SLE, Churg-Strauss)

Question 21

What are the causes of thrombocytopenia? (PLATELETS)

Answer 21

P: Platelet disorders (DIC, TTP, ITP)

L: Leukaemia

A: Anaemia

T: Trauma

E: Enlarged spleen

L: Liver disease

E: Ethanol (alcohol eg. heavy drinking)

T: Treatment (heparin, aspirin, chemo)

S: Sepsis

Question 22

What are the causes of thrombocytosis?

Answer 22

Essential thrombocythemia

Secondary thrombocytosis

Pregnancy

Post-splenectomy