Given the frequency and consistency with which these autoimmune adverse effects appear, many physicians advocate screening all patients treated with anti-CTLA-4 agents for endocrinopathies with measurements of morning serum cortisol level, electrolytes (to detect hyponatremia or hyperkalemia as indicators of adrenalitis), TSH, and free T4 levels. This evidence concerns the gene CTLA4 and Hyperkalemia.