A finding of cytogenetic abnormalities, even when these are clonal and even when the abnormalities are typically associated with leukaemia, is not the same as a person having leukaemia. We describe a person who had acute myeloid leukaemia (AML) and achieved a complete haematological remission and who then had persistent and transient clonal cytogenetic abnormalities for 22 years but no recurrence of leukaemia. These data suggest that clones of myeloid cells with mutations and capable of expanding to levels detectable by routine cytogenetic analyses do not all eventuate in leukaemia, even after a prolonged observation interval. The possibility of incorrectly diagnosing a person as having leukaemia becomes even greater when employing more sensitive techniques to detect mutations such as by polymerase chain reaction and whole-exome or whole-genome sequencing. Caution is needed when interpreting clonal abnormalities in AML patients with normal blood and bone marrow parameters.