Initial investigations in the emergency department
Full blood count (FBC)
The suspicion of acute leukaemia will usually be raised by the FBC. Acute leukaemia normally causes leucocytosis, although a leucopaenic or pancytopaenic picture can be seen.
A haematological disorder is more likely if there are abnormal counts in at least two cell lines (e.g. anaemia with thrombocytopaenia), known as bicytopaenia.
Blood film
If leukaemia is suspected, a blood film should be requested as the first-line investigation (although commonly this will already have been requested within the laboratory).
Acute leukaemia is characterised by the appearance of “blasts” (immature white blood cells) on the blood film. A diagnosis of acute leukaemia is made if blasts account for over 20% of the total white cell count in either peripheral blood or bone marrow3.
Occasionally, very few or no blasts will be seen within the peripheral blood; this does not rule out the presence of an underlying leukaemia within the bone marrow. A haematology referral can be made to consider a bone marrow test to investigate further.
This image shows the typical appearance of a blast on a peripheral blood film.
1.Question
A young female presents complaining of lethargy, malaise, oro-mucosal tingling and weight loss which have gradually worsened over 6 months. Her FBC is shown below.
| Haemoglobin (g/L) | 50 (115-165) |
| Mean Cell Volume (fl) |
120 (80-100) |
| Platelets (109/L) |
60 (150-400) |
| White cell count (109/L) |
2 (4-11) |
| Neutrophil count (109/L) |
1.2 (2-7.5) |