Which initial investigations should be performed for a patient suspected of having leukaemia?

Initial investigations for a patient suspected of having leukaemia should include a very urgent full blood count (FBC) to be performed within 48 hours. This is recommended for adults presenting with symptoms such as pallor, persistent fatigue, unexplained fever, unexplained persistent or recurrent infection, generalized lymphadenopathy, unexplained bruising, unexplained bleeding, unexplained petechiae, or hepatosplenomegaly.

In children and young people, immediate specialist assessment is advised if they have unexplained petechiae or hepatosplenomegaly. Additionally, a very urgent full blood count (within 48 hours) should be offered if they present with pallor, persistent fatigue, unexplained fever, unexplained persistent infection, generalized lymphadenopathy, persistent or unexplained bone pain, unexplained bruising, or unexplained bleeding.

These initial blood tests help identify haematological abnormalities suggestive of leukaemia and guide urgent referral and further specialist investigations.

Referral to specialist haematology services should be considered promptly based on these initial findings.

This approach aligns with the NICE guideline Suspected cancer: recognition and referral and the CKS guidance on haematological cancers.

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