Guided Study: Data Interpretation: Full Blood Count

Question 1

Define the Clinical Method.

Answer 1

Series of steps which allow you to reason through to the diagnosis and management of patients:

1. History (Hx)
2. Differential diagnosis (DD)
3. Examination: look for evidence to support your DD
4. Differential diagnosis: further refined following examination
5. Working diagnosis
6. Proposed investigations to confirm provisional working diagnosis (must be able to justify your proposed investigations)
7. Results of investigations e.g. full blood count
8. Management plan (Mx)
9. Review of progress of management of disease process

Question 2

What does raised WBC count suggest ?

Answer 2

Infection, inflammation, an immune response, or blood diseases such as leukaemia

Question 3

What does neutrophilia suggest ?

Answer 3

Bacterial infection

Question 4

Define Menorrhagia.

Answer 4

Abnormally heavy and prolonged, regular periods resulting in excessive blood loss

Question 5

Describe your clinical plan for a patient exhibiting the following symptoms: temperature 38.40C in an elderly male patient.

Answer 5

1. Commonest cause of fever is infection
2. Order investigations, proposing that the White Blood Count (WBC) will be high (fighting the infection). The WBC is part of the FBC.
3. Look at the White Blood Count - is it normal, raised or reduced? If raised: it would suggest infection
4. Next look at the differential WBC to evaluate the type of infection e.g. neutrophilia would suggest a bacterial infection
5. Seek the site of infection: e.g. blood, urine, chest, abdomen
6. Manage with appropriate antibiotic
7. Review patient and vital signs. Are there signs of improvement?
8. Reassess WBC and differential to monitor improvement

Question 6

Describe your clinical plan for a patient exhibiting the following symptoms: tiredness and light headedness in a menopausal woman with menorrhagia (abnormally heavy and prolonged, regular periods resulting in excessive blood loss). No Gastrointestinal (GI) symptoms on questioning.

Answer 6

1) One possible cause of tiredness would be anaemia due to menorrhagia
2) Examination: to confirm signs of anaemia e.g. pallor, koilonychia
3) Working diagnosis: - the patient is anaemic secondary to excessive chronic blood loss.
4) Order investigations, proposing that in anaemia the Hb will be low in the Full Blood Count.
5) If Hb is low: Conclusion: Patient is anaemic. Now need to classify the type of anaemia

6) Next look at the indices: If low both MCV and MCH
A microcytic, hypochromic anaemia suggests iron deficiency anaemia

7) Next need to further investigate the extent of the iron deficiency
e.g. perform iron studies: Ferritin - propose that ferritin will be low
Result: Low ferritin: the body is lacking in stores of iron having been used up

8) Management Plan (Mx):
i) Confirm the cause of the anaemia: chronic blood loss and/or nutritional deficiency ii) Manage menorrhagia e.g. hormonal therapy, IUD
iii) Give oral iron and improve the intake of iron in the diet

9) Following a period of management reassess the patient and symptoms:
Repeat the Full Blood count and ferritin: increased Hb, increased MCV, increased MCH, increased reticulocytes, increased ferritin looking for evidence of improvement.

Question 7

What are abnormal Hb ranges for men and women ?

Answer 7

Men: < 135g/l
Women: < 115g/l

Question 8

What steps much be taken if Hb range below norm ?

Answer 8

1) Clinical evaluation and blood film if abnormal cells/pancytopenia (reduction in the number of red and white blood cells, as well as platelets)

2)
If MCV <80 fl, check ferritin and ESR.
- If ferritin low: consider iron deficiency anaemia
- If ferritin normal or raised and ESR raised: consider anaemia of chronic disease

If MCV 80- 100 fl, check ferritin, U&Es, LFTs, reticulocytes. 
Consider
- chronic disease
- early iron deficiency anaemia
- renal disease
- primary marrow disease
- haemolysis, bleeding

If MCV >100 fl, check B12/folate, LFTs, TFTs, ferritin, reticulocytes, protein electrophoresis.
Consider
- alcohol excess
- Vit B12/folate deficiency
- drugs
- liver disease
- thyroid disease 
- haemolysis
- myelodysplasia (type of cancer in which the bone marrow does not make enough healthy blood cells and there are abnormal (blast) cells in the blood and/or bone marrow)