Ferritin is not a very good test for iron level. MRI scans of the liver and heart are done to determine the true iron level. Because natural chelators are being used and there is no way to know how well they are working, at some point, a liver MRI should be done to check the iron load in the liver. If the skin tone of a patient lightens, it is a sign that iron is being removed. If MRI is unavailable at this time, continue to monitor the ferritin and the overall health of the patient. You don't want to go too long without verifying that enough iron is being removed to keep the patient safe, so at some point, the MRI does need to be done.