It is interesting to note however, that a 2021 study conducted in gastroenterology patients in the United Kingdom35 has shown that non-traditional markers such as hepcidin, soluble transferrin receptor (sTfR), sTfR/log ferritin index, and reticulocyte haemoglobin equivalent, can be used to correctly reclassify a substantial proportion of patients in this group as either IDA or ACD alone, indicating that using only traditional markers may overstate the true prevalence of iron deficiency + ACD.37 However, these markers are not without limitations. This evidence concerns the gene TFRC and granular corneal dystrophy type II.