Additional diagnostic studies in anorexia nervosa are used to assess complications of starvation, evaluate physiologic consequences, and exclude alternative diagnoses, rather than to establish the diagnosis itself. Testing should be guided by clinical findings and illness severity.^[1][2]

• Dual-energy X-ray absorptiometry (DEXA) is recommended to evaluate:
  • Decreased bone mineral density
  • Osteopenia or osteoporosis
• Indicated particularly in individuals with prolonged amenorrhea, delayed puberty, or chronic illness^[1][2][3]

• Reproductive hormone testing (LH, FSH, estradiol or testosterone) may demonstrate hypothalamic hypogonadism
• Useful in evaluating amenorrhea, delayed puberty, or growth disturbance^[1][2]

• Continuous cardiac monitoring may be required in individuals with:
  • Severe bradycardia
  • QTc prolongation
  • Significant electrolyte abnormalities
• Used to detect arrhythmias and assess medical instability^[1][2][3][4]

• Review of growth curves and pubertal development is essential in children and adolescents
• Delayed or arrested growth may indicate prolonged or severe disease^[2][5]

• Comprehensive psychiatric assessment is recommended for all individuals with suspected anorexia nervosa
• Evaluation should include assessment for:
  • Mood disorders
  • Anxiety disorders
  • Obsessive-compulsive disorder
  • Suicidality^[2][6][7][8]

Aside from laboratory testing, ECG, and bone density assessment, diagnostic studies in anorexia nervosa are selective and problem-driven. Their primary role is to evaluate complications, assess severity, and exclude alternative medical or psychiatric conditions.