The flow cytometric diagnosis of AML

Acute leukaemia types

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In most cases a diagnosis of AML by flow cytometry is relatively straightforward, and can be addressed in a structured manner. The key is to ensure atypical cases are identified and unusual diagnoses are not missed. The workflow here is based on WHO criteria.

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Question 1. Do the cells have flow cytometric features that support their primitive nature?
Blast cells typically have "primitive" morphology and also express markers of early differentiation

• Most often in AML useful features of immature cells are weak expression of CD45, and expression of CD34 and/or CD117. However, a wider panel may be useful (for more detail see Markers used to demonstrate primitive nature in AML)
• In some cases there may be atypical features where primitive nature is less clear, this generally concerns some monocytic cases or APL (see table for details)

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Can we confirm myeloid nature?

• Typical cases can generally be recognised by (see table for details)
• Atypical cases can still be identified based on a minimal feature set (see table for details)
• In unusual cases an extended marker panel may allow lineage assignment (see Table for details)

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Are there atypical features?

• Expected abberency
• Feature that may give concern

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