In this lecture we will review the meaning and relevance of the results provided by automated haematology analysers, focusing on erythrocyte and leukocyte parameters. We will briefly review the different methodologies of analysis, to allow critical assessment of the results provided by in-house analysers. We will discuss the significance of the parameters, recognition of pattern of changes, their interpretation and clinical relevance. We will discuss what information flags and dot plots provide and how to integrate them in interpretation of results and guidance for blood smear review.