Original Article This work is licensed under the Creative Commons Attribution 4.0 License. Published by Pacifc Group of e-Journals (PaGe) Utility Of Frozen Section Versus IOPTH In Parathyroid Surgery Introduction With the widespread use of radioactive technetium-99m sestamibi scan, the localization of parathyroid has become accurate. This has led to an increase in minimally invasive surgical procedures with smaller surgical incisions. [1] As the half-life of parathyroid hormone (PTH) is very short (2-5 minutes), taking the preoperative PTH levels as the baseline, rapid intra-operative parathyroid hormone (IOPTH), also called the chemical frozen section, sent 5-10 minutes after the removal of the enlarged gland provides an excellent method to assess the completion of the surgery. [2] A fall of >50% in the PTH levels indicates successful removal of the hormone producing tumor. Thus, in the era of ‘chemical frozen section’, the ‘original’ frozen section is essential in certain specifc situations, like when the drop in PTH is not as expected, or when there are multiple nodules, either parathyroid or the adjacent thyroid or even lymph nodes or the thymus. It is also indicated in cases of an infltrating neck mass where parathyroid carcinoma is suspected or in cases with extreme hypercalcemia. [2] Materials and Methods This was a retrospective study, conducted in a tertiary care center in South India during the period of January 2015 to December 2017. This study was performed in accordance with the principles of the Declaration of Helsinki. Data was retrieved from the records in the department of Pathology and the digital records in Laboratory Information System (LIS). Patient details were coded, and direct and indirect identifers were avoided. The data of specimens of parathyroid tissue sent for frozen section were identifed. Then LIS was used to identify those cases which had an IOPTH sent around the same time (+/-10 minutes) as the frozen section. Parathormone (PTH) was assessed by chemilumiscence method. The gold standard for fnal diagnosis was histopathology following parafn embedding along with fall in the parathormone levels. Inclusion criteria: Parathyroidectomies which had both frozen section (FS) and IOPTH Exclusion criteria: Parathyroidectomies having only FS and those with neither FS nor IOPTH The imprint smears, frozen sections and histopathology slides were retrieved and reviewed. Imprint smears and frozen sections were stained by rapid haematoxylin and eosin (H&E). The results were tabulated and analyzed. Results A total of 672 cases were received for frozen section, by the department of Pathology during the period between January 2015 and December 2017. Of these, the parathyroid tissue Shiva Prasad 1 , Padmapriya Jaiprakash 2 * 1 Manipal Academy of Higher Education, Karnataka - 576104, India 2 Manipal Academy of Higher Education, Karnataka - 576104, India ABSTRACT Introduction: Parathyroid surgeries are becoming less extensive procedures, with reduced hospital stay. The use of intraoperative frozen section help the surgeon in identifying the pathology, thereby determining the nature of surgery. Aim: To study the utility of frozen section in comparison to chemical frozen section in our set up Materials and Methods: Data was collected from records of department of Pathology during a period of 3 years. Only those cases were included in which the patient had undergone parathyroidectomy, with specimen being sent for frozen section and intra-operative parathyroid hormone (IOPTH) simultaneously. Results: Frozen section diagnosis was concordant in 11/15 (73%) cases. Signifcant percentage drop in IOPTH was seen in 13/15 (86%) cases. We found frozen section useful in identifying parathyroid when there were multiple neck swellings. Conclusion: The utility of frozen section in parathyroid surgery is diminishing and it is being replaced by better and more accurate biochemical assays. Keywords: Frozen, Parathyroid, Chemical DOI: 10.21276/APALM2181