PTH and Hypocalcemia: In predicting hypocalcemia, the best cutoff values for PTH-SC and PTH-D1 were ≤1.0 pmol/L (Youden’s index = 0.774; sensitivity 82.4 % and specificity 95.0 %) and ≤0.6 pmol/L (Youden’s index = 0.695; sensitivity 76.5 % and specificity 93.0 %), respectively.