Abstract Aim The study aimed to investigate the causes of temporary postoperative hypocalcemia and strategies for correction. Objectives included assessing the impact of preoperative trust guidelines on detecting and managing Vitamin D deficiency in thyroidectomy patients and analyzing its correlation with postoperative hypocalcemia at Northampton General Hospital. Method A three-cycle audit analyzed 16, 12, and 8 cases, respectively, encompassing total and completion thyroidectomies at NGH. Collaborative development of standardized trust guidelines involved the ENT Team, Endocrinology, and Pharmacists. Data collection covered various parameters, and departmental teachings were conducted to educate the team on the new guidelines. Results Thyroidectomy indications included Graves's disease, large Multinodular Goitre, and malignancy. In the third cycle, all patients underwent preoperative Vitamin D checks, aligning postoperative hypocalcemia with the national range. Our interventions increased preoperative Vitamin D checks from 56% to 100%, reducing deficiency from 25% to 0%. Postoperative hypocalcemia decreased from 56% in Cycle 1 to 8.3% in Cycle 2 and 12.5% in Cycle 3. Long-term hypoparathyroidism dropped to 0% in Cycle 3, with no correlation between surgeon technique or indication and postoperative hypocalcemia. Conclusions The introduction of preoperative guidelines significantly enhanced Vitamin D deficiency detection, substantially reducing postoperative hypocalcemia. This underscores the positive impact of standardized protocols on patient care. Future efforts involve re-auditing with the involvement of junior doctors to ensure continuous enhancement in clinical practice.