3.1.2 Specialist testing (including genetic testing)

Specialised testing is performed to:

  • ensure accurate diagnoses
  • accurately sub-classify AML
  • inform prognosis
  • inform treatment decisions that are evidence-based.

Classification is the principle process by which key information is collated to inform prognosis and management of patients with AML.

Classification and risk stratification for AML involves these tests:

  • morphological assessment
  • cytogenetics
  • flow cytometry
  • molecular pathology (genetic testing).

AML is classified according to the World Health Organization’s classification of AML tumours (Arber et al. 2016). The European LeukemiaNet stratification system classifies patients as having favourable, intermediate and adverse risk based on karyotype, selected molecular abnormalities (currently FLT3, NPM1, TP53, ASXL1, RUNX1 and CEBPA mutation status) (Döhner et al. 2017).

The other most important prognostic features are age at diagnosis, performance status, presence of extramedullary disease, hyperleukocytosis, therapy-related AML (previous exposure to cytotoxics), presence of an antecedent bone marrow failure syndrome and response to induction chemotherapy.

Newer molecular markers with prognostic and therapeutic relevance in AML are likely to become clinically routine in the near future (Grimwade et al. 2016).

Most genetic abnormalities in AML only occur in abnormal blood cells and are not related to genetic abnormalities that affect the whole body and/or are inherited. However, heritable genetic abnormalities may be identifiable in a very small number of patients. AML with a genetic predisposition is an entity in the World Health Organization classification, and most diagnostic centres have access to identification of heritable genetic abnormalities related to leukaemia. This becomes significantly relevant if a family member is being considered as a stem cell donor.