GSTM1 and anemia (phenotype): The increase in anaemia prevalence, from 3.9% based on clinical diagnosis in the hospital data compared to 19.4% according to pathology results, however, highlights discrepancies between the language clinicians use in the medical notes and the language required for clinical coding, such that Hb = 69 g/L cannot be interpreted as anaemia by a coder if the words ‘anaemia’ or ‘low Hb’ are not written in the notes [17].