Hypocalcemia is the most common complication after total thyroidectomy. Intact parathyroid hormone (i-PTH) testing is a proven effective method to detect patients at risk for postoperative symptomatic hypocalcemia. However, there is still uncertainty as to the timing of i-PTH testing in a clinical setting. Objective: This study looked into the correlation between serum i-PTH levels measured at different times after total thyroidectomy and the risk of symptomatic hypocalcemia. Methods: This retrospective case series studied a group of 110 consecutive for hypocalcemia and intact parathyroid hormone (PTHi) levels four and twelve hours following total thyroidectomy. Statistical analysis was used to evaluate the performance of isolated and serial i-PTH measurements to determine the likelihood of symptomatic hypocalcemia. Results: I-PTH is highly sensitive (90.3%-96.8%) and specific (77.2%-87.3%) for symptomatic hypocalcemia. There was no significant difference in the sensitivity levels of the tests done four and twelve hours after surgery or in a serial fashion. However, the 12-hour i-PTH level was more specific (p < 0.0007). Conclusion: Single i-PTH testing done 12 hours after total thyroidectomy may be used as a screening test to detect patients at risk for symptomatic hypocalcemia.7857882Al-Suliman, N.N., Ryttov, N.F., Qvist, N., Blichert-Toft, M., Graversen, H.P., Experience in a specialist thyroid surgery unit: A demographic study, surgical complications, and outcome (1997) Eur J Surg, 163 (1), pp. 13-20Wilson, R.B., Erskine, C., Crowe, P.J., Hypomagnesemia and hypocalcemia after thyroidectomy: Prospective study (2000) World J Surg, 24 (6), pp. 722-726Bergenfelz, A., Jansson, S., Kristoffersson, A., Martensson, H., Reihnér, E., Wallin, G., Complications to thyroid surgery: Results as reported in a database from a multicenter audit comprising 3,660 patients (2008) Langenbecks Arch Surg, 393 (5), pp. 667-673Glinoer, D., Andry, G., Chantrain, G., Samil, N., Clinical aspects of early and late hypocalcaemia after thyroid surgery (2000) Eur J Surg Oncol, 26 (6), pp. 571-577Tovi, F., Noyek, A.M., Chapnik, J.S., Freeman, J.L., Safety of total thyroidectomy: Review of 100 consecutive cases (1989) Laryngoscope, 99 (12), pp. 1233-1237Jafari, M., Pattou, F., Soudan, B., Devos, M., Truant, S., Mohiedine, T., Étude prospective des facteur prédictifs precoces de la survenue d'hipocalcémie définitive aprés thyroidectomie bilatérale (2002) Ann Chir, 127 (8), pp. 612-618Proye, C., Carnaille, B., Maynou, C., Bizard, J.P., Gilliot, P., Lariviere, J., Le risque parathyroïdien en chirurgie thyroïdienne (1990) Chirurgie, 116 (6-7), pp. 493-500Megherbi, M.T., Graba, A., Abid, L., Oulmane, D., Saidani, M., Benabadji, R., Complications et séquelles de la chirurgie thyroïdienne bénigne (1992) J Chir, 129 (1), pp. 41-46Khairy, G.A., Al-Saif, A., Incidental parathyroidectomy during thyroid resection: Incidence, risk factors, and outcome (2011) Ann Saudi Med, 31 (3), pp. 274-278Pattou, F., Combemale, F., Fabre, S., Carnaille, B., Decoulx, M., Wemeau, J.L., Hypocalcemia following thyroid surgery: Incidence and prediction of outcome (1998) World J Surg, 22 (7), pp. 718-724Del Rio, P., Arcuri, M.F., Ferreri, G., Sommaruga, L., Sianesi, M., The utility of serum PTH assessment 24 hours after total thyroidectomy (2005) Otola-ryngol Head Neck Surg, 132 (4), pp. 584-586Youngwirth, L., Benavidez, J., Sippel, R., Chen, H., Parathyroid hormone deficiency after total thyroidectomy: Incidence and time (2010) J Surg Res, 163 (1), pp. 69-71Roh, J.L., Park, C.I., Routine oral calcium and vitamin D supplements for prevention of hypocalcemia after total thyroidectomy (2006) Am J Surg, 192 (5), pp. 675-678Sabour, S., Manders, E., Steward, D.L., The role of rapid PACU parathyroid hormone in reducing post-thyroidectomy hypocalcemia (2009) Otolaryngol Head Neck Surg, 141 (6), pp. 727-729Aluffi, P., Aina, E., Bagnati, T., Toso, A., Pia, F., Prognostic factors for definitive hypoparathyroidism following total thyroidectomy (2008) Acta Otorrinolaringol Esp, 59 (7), pp. 321-324Lindblom, P., Westerdahl, J., Bergenfelz, A., Low parathyroid hormone levels after thyroid surgery: A feasible predictor of hypocalcemia (2002) Surgery, 131 (5), pp. 515-520Postoperative parathyroid hormone measurement and early discharge after total thyroidectomy: Analysis of Australian data and management recommendations (2007) ANZ J Surg, 77 (4), pp. 199-202. , AES Guidelines 06/01 Group. Australian Endocrine Surgeons Guidelines AES/06/01Hermann, M., Ott, J., Promberger, R., Kober, F., Karik, M., Freissmuth, M., Kinetics of serum parathyroid hormone during and after thyroid surgery (2008) Br J Surg, 95 (12), pp. 1480-1487Husein, M., Hier, M.P., Al-Abdulhadi, K., Black, M., Predicting calcium status post thyroidectomy with early calcium levels (2002) Otolaryngol Head Neck Surg, 127 (4), pp. 289-293Adams, J., Andersen, P., Everts, E., Cohen, J., Early postoperative calcium levels as predictors of hypocalcemia (1998) Laryngoscope, 108 (12), pp. 1829-1831Gao, P., Scheibel, S., D'Amour, P., John, M.R., Rao, S.D., Schmidt-Gayk, H., Development of a novel immunoradiometric assay exclusively for biologically active whole parathyroid hormone 1-84: Implications for improvement of accurate assessment of parathyroid function (2001) J Bone Miner Res, 16 (4), pp. 605-614Goodman, W.G., The evolution of assays for parathyroid hormone (2005) Semin Dial, 18 (4), pp. 296-301Noordzij, J.P., Lee, S.L., Bernet, V.J., Payne, R.J., Cohen, S.M., McLeod, I.K., Early prediction of hypocalcemia after thyroidectomy using parathyroid hormone: An analysis of pooled individual patient data from nine observational studies (2007) J Am Coll Surg, 205 (6), pp. 748-754Grodski, S., Serpell, J., Evidence for the role of perioperative PTH measurement after total thyroidectomy as a predictor of hypocalcemia (2008) World J Surg, 32 (7), pp. 1367-1373Soon, P.S., Magarey, C.J., Campbell, P., Jalaludin, B., Serum intact parathyroid hormone as a predictor of hypocalcaemia after total thyroi-dectomy (2005) ANZ J Surg, 75 (11), pp. 977-980Sywak, M.S., Palazzo, F.F., Yeh, M., Wilkinson, M., Snook, K., Sidhu, S.B., Parathyroid hormone assay predicts hypocalcaemia after total thyroidectomy (2007) ANZ J Surg, 77 (8), pp. 667-670Toniato, A., Boschin, I.M., Piotto, A., Pelizzo, M., Sartori, P., Thyroidectomy and parathyroid hormone: Tracing hypocalcemia-prone patients (2008) Am J Surg, 196 (2), pp. 285-288Scurry, W.C., Beus, K.S., Hollenbeak, C.S., Stack, B.C., Perioperative parathyroid hormone assay for diagnosis and management of post-thyroidectomy hypocalcemia (2005) Laryngoscope, 115 (8), pp. 1362-1366Di Fabio, F., Casella, C., Bugari, G., Iacobello, C., Salerni, B., Identification of patients at low risk for thyroidectomy-related hypocalcemia by intraoperative quick PTH (2006) World J Surg, 30 (8), pp. 1428-1433Khafif, A., Pivoarov, A., Medina, J.E., Avergel, A., Gil, Z., Fliss, D.M., Parathyroid hormone: A sensitive predictor of hypocalcemia following total thyroidectomy (2006) Otolaryngol Head Neck Surg, 134 (6), pp. 907-910Erbil, Y., Bozbora, A., Ozbey, N., Issever, H., Aral, F., Ozarmagan, S., Predictive value of age and serum parathormone and vitamin d3 levels for postoperative hypocalcemia after total thyroidectomy for nontoxic multinodular goiter (2007) Arch Surg, 142 (12), pp. 1182-1187Wiseman, J.E., Mossanen, M., Ituarte, P.H., Bath, J.M., Yeh, M.W., An algorithm informed by the parathyroid hormone level reduces hypocalcemic complications of thyroidectomy (2010) World J Surg, 34 (3), pp. 532-537Vescan, A., Witterick, I., Freeman, J., Parathyroid hormone as a predictor of hypocalcemia after thyroidectomy (2005) Laryngoscope, 115 (12), pp. 2105-2108Lam, A., Kerr, P.D., Parathyroid hormone: An early predictor of post-thyroidectomy hypocalcemia (2003) Laryngoscope, 113 (12), pp. 2196-2200Payne, R.J., Tewfik, M.A., Hier, M.P., Tamilia, M., Mac Namara, E., Young, J., Benefits resulting from 1- and 6-hour parathyroid hormone and calcium levels after thyroidectomy (2005) Otolaryngol Head Neck Surg, 133 (3), pp. 386-390