Neutrophils

Neutrophils Result

(Reference range: 1.50-6.10 ×10⁹/L)

 

What is Neutropenia?

Neutropenia refers to a reduced neutrophil count, typically < 1.5 ×10⁹/L in adults. It may be mild, moderate or severe depending on the value and often signals bone marrow suppression, infection or autoimmune disease.

  • Mild: 1.0-1.5 ×10⁹/L
  • Moderate: 0.5-1.0 ×10⁹/L
  • Severe: < 0.5 ×10⁹/L (higher risk of serious infections)

Common Causes

  • Viral infections (e.g. influenza, EBV, hepatitis)
  • Bone marrow suppression (e.g. chemotherapy, aplastic anaemia)
  • Medications (e.g. carbimazole, clozapine, sulfasalazine)
  • Autoimmune disease (e.g. SLE, Felty’s syndrome)
  • Overwhelming sepsis
  • HIV or haematological malignancy

Stepwise Clinical Approach

Step 1: Confirm and Repeat

Confirm that neutrophil count is truly reduced. If recent infection or medication change, repeat FBC in 1-2 weeks.

Step 2: Identify Red Flags

  • Neutrophils < 0.5 ×10⁹/L
  • Fever or clinical signs of infection
  • Associated anaemia or thrombocytopenia
  • Weight loss, lymphadenopathy or splenomegaly

If any present → refer urgently (e.g. haematology or hospital admission if febrile).

Step 3: Medication and Infection History

  • Check for recent or chronic infections
  • Review medications known to cause neutropenia
  • Any history of chemotherapy or radiation?

Transient neutropenia post-infection is common.

Step 4: Consider Further Investigations

  • HIV test if risk factors present
  • ANA, ENA if autoimmune disease suspected
  • Blood film if unexplained or persistent
  • Bone marrow biopsy if suspected marrow failure

Step 5: Monitor or Refer

  • Mild neutropenia: monitor in primary care if stable and improving
  • Moderate or persistent: refer non-urgently to haematology
  • Febrile neutropenia: emergency referral/hospital admission
 

What is Neutrophilia?

Neutrophilia refers to an elevated neutrophil count, typically > 6.10 ×10⁹/L in adults. It is often reactive to infection or inflammation, but persistent or very high counts may warrant further investigation.

Common Causes

  • Bacterial infections (especially acute or localised)
  • Inflammatory conditions (e.g. trauma, burns, MI)
  • Stress response (e.g. surgery, seizures)
  • Medications (e.g. corticosteroids, lithium)
  • Smoking
  • Myeloproliferative disorders (e.g. chronic myeloid leukaemia)

Stepwise Clinical Approach

Step 1: Confirm and Contextualise

Review the absolute neutrophil count. Was the blood taken during illness, after trauma, or on steroids?

Step 2: Identify Reactive Causes

  • Check for infection, inflammation, or recent stress events
  • Review medication history (especially corticosteroids)
  • Repeat FBC in 2-3 weeks if a temporary cause is suspected

Reactive neutrophilia is usually transient and self-resolving.

Step 3: Examine the Full Blood Count

  • Are other counts abnormal (e.g. eosinophilia, basophilia, thrombocytosis)?
  • Review blood film if persistent or unexplained
  • Consider ESR/CRP, liver function, ferritin for inflammation clues

Step 4: Monitor or Refer

  • If improving or reactive: monitor and repeat in primary care
  • If persistent > 15 ×10⁹/L for > 3 months: consider haematology referral
  • If splenomegaly or other red flag symptoms present: refer earlier

Step 5: Red Flags Requiring Urgent Action

  • Neutrophilia with unexplained weight loss, fever, or night sweats
  • Concurrent anaemia or thrombocytosis
  • Very high count (e.g. > 30 ×10⁹/L) without infection
  • Basophilia or eosinophilia suggesting a myeloproliferative process

Consider urgent referral to haematology if red flags are present.

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