Neutropenia in primary careBMJ 2014; 349 doi: https://doi.org/10.1136/bmj.g5340 (Published 11 September 2014) Cite this as: BMJ 2014;349:g5340
- Deborah Hay, specialist registrar in haematology1,
- Matilda Hill, clinical medical student2,
- Tim Littlewood, consultant haematologist1
- 1Department of Haematology, Oxford University Hospitals NHS Trust, Oxford, UK
- 2Oxford University Clinical Medical School, Oxford, UK
- Correspondence to: T Littlewood
Isolated neutropenia is a common incidental finding in primary care. It is most often drug induced or caused by acute viral infection
Benign ethnic neutropenia is common in people of black African and Afro-Caribbean ethnicity
It is rare for primary haematological malignancy to present with isolated neutropenia because other haemopoietic cells lines are usually also affected
The initial investigation of persistent isolated neutropenia should include a peripheral blood film, haematinics, and chronic viral serology
No formal diagnosis can be reached in many adults with isolated neutropenia
Referral for haematological assessment is warranted if anaemia or thrombocytopenia is also evident, or when persistent neutropenia is moderate or severe (<1×109/L)
A mild neutropenia of 1.2×109/L is detected in a 69 year old man who presents with a short history of fatigue. He takes no regular drugs. The rest of his blood count is normal, as is his physical examination.
Is further investigation needed?
Neutropenia is defined as an absolute neutrophil count of less than 1.5×109/L. It is important for two reasons. Firstly, it may indicate an underlying systemic or haematological disease. Secondly, it reflects an increased risk of life threatening bacterial infection—risk increases once the count is less than 1.0×109/L and becomes even greater in severe neutropenia (box).1 2
Severity of neutropenia
Mild: 1.0-1.5×109 neutrophils/L
Moderate: 0.5-0.9×109 neutrophils/L
Severe: <0.5×109 neutrophils/L
The General Practice Research Database suggests that 1:100 000 patients per year receive an ICD (International Classification of Diseases) code for neutropenia or agranulocytosis.3 Although data are limited, we can assume that many more have transient or mild neutropenia. The more severe the neutropenia, the more likely it is that further investigation will be initiated, although no strict guidelines exist for this. Table 1⇓ highlights important causes of isolated neutropenia.