Is there scientific evidence to adjust haemoglobin by altitude to define anaemia?

Comment on a recent publication in Nutrients entitled ¨Adjusting Haemoglobin Values for Altitude Maximizes Combined Sensitivity and Specificity to Detect Iron Deficiency among Women of Reproductive Age in Johannesburg, South Africa¨. A statistical evaluation has been carried out on the use of haemoglobin and ferritin for iron deficiency and anaemia deficiency diagnose, through the use of ROC curves and categorization of different cut points, in a population of women living at sea level