A smartphone app for the non-invasive detection of anaemia using patient-supplied photographs detected anaemia (Hb levels 12.5 g/dL) with an accuracy of 2.4 g/dL and a sensitivity of 97% (95% CI, 89-100%) when compared to complete blood count (CBC) Hb levels (n=100 subjects) [21]. A recent review article highlights the potential of non-invasive systems for the monitoring and early detection of anaemia, which is a significant problem [22]. The gene discussed is GSTM1; the disease is anemia.