Pre-treatment medical investigations will be performed on the day of presentation to the specialist cancer service. Other results necessary for immediate management decisions should be available within 72 hours of the patient presenting.

The diagnostic laboratory investigations should be performed as follows.

Urgent pathway

For urgent cases, if it is safe to do so, the diagnostic bone marrow aspiration and LP should be performed on the day of presentation. Urgent patients include, but are not limited to, those who present with hyperleukocytosis, tumour lysis syndrome, mediastinal mass and coagulopathies, and those with suspected APL.

If there is a suspicion of APL, urgent treatment with all-trans retinoic acid should be instigated immediately.

Standard pathway

The diagnostic bone marrow aspiration and LP should be performed by the next business day; however, clinical trial requirements, as well as the level of institutional resources, should also guide timings.

Measurable/minimal residual disease

As above, the importance of this test for measuring response to treatment in CAYAs with acute leukaemia cannot be overstated. A sample for MRD is collected at diagnosis and then at regular time points during therapy to assess response. The exact time points depend on the diagnosis (ALL or AML), the enrolled clinical trial or treatment algorithm for the patient.

Refer to sections 4.2.1 and 4.2.2 for general principles for MRD monitoring in CAYA leukaemias.