PTH and chronic kidney disease: It may be the result of: 1) autonomous secretion of PTH by parathyroid glands (primary hyperparathyroidism, PHPT); 2) excessive secretion of hormone as a consequence of chronic hypocalcemia in patients with chronic renal failure (secondary hyperparathyroidism, SHPT); 3) functional autonomy of parathyroid glands occurs during a long-lasting secondary hyperparathyroidism (tertiary hyperparathyroidism, THPT) (1, 2).