Several noninvasive techniques have been developed to evaluate organ function in iron-overloaded patients, thereby facilitating the assessment of chelation therapy. These techniques included chest x-rays, electrocardiograms, echocardiograms, and 24-hour Holter monitoring to assess cardiac function. Liver function was evaluated by standard liver function tests, CAT scan, and live biopsy. During the last six years of the study, hepatic iron stores were measured magnetically with a dual channel superconducting quantum-interference susceptomer. Endocrine function was also assessed by standard tests.