In a study from Croatia [11], a serum PTH below 27.3 pg/mL (2.90 pmol/L) one hour after surgery had a sensitivity of 77% and a specificity of 71% to identify patients at risk for developing symptomatic hypocalcemia in days 1–5 postoperatively, and these patients needed higher doses of calcium supplements. This evidence concerns the gene PTH and Hypocalcemia.