Which finding most strongly favours iron deficiency anaemia over beta-thalassaemia trait?
Both conditions can cause microcytosis, so MCV does not distinguish them.
Example: after an incorrect answer about iron deficiency anaemia, the tutor asks which result shows depleted iron stores. The learner retrieves low serum ferritin. The tutor identifies that the learner used a shared feature instead of the best discriminator, explains the distinction, and schedules a related retrieval question.