ACCURACY OF INTRAOPERATIVE FROZEN SECTION: REVIEW OF TWO YEARS EXPERIENCE AT CHUGHTAI INSTITUTE OF PATHOLOGY

Abstract

Objectives: To evaluate diagnostic accuracy, sensitivity and specificity alongwith indications, limitations, common causes of discrepancies and deferral of intraoperative frozen section consultation by comparing frozen section diagnosis with the final diagnosis.

Material & Methods: This is a cross sectional study conducted at the department of histopathology, Chughtai Institute of Pathology, Lahore Pakistan. A total of 278 consecutive cases in which frozen section was performed over a period of two years from 1^st January 2018 to 31st December 2019 were studied. The frozen section diagnosis was compared with the final histopathological diagnosis rendered on formalin-fixed tissue in all cases.

Results: Out of 278 cases, 6 were deferred for routine histopathological diagnosis resulting in a deferral rate of 2.15%. In the remaining 272 cases, results were concordant in 267 cases (98.16%) while 5 (1.83%) cases showed discordant results. The diagnostic accuracy was found to be 98.2% with the false positive diagnosis of malignancy in 1.10% and false negative diagnosis in 3.33% cases.  The overall sensitivity and specificity was 96.7% and 98.9% respectively. The most common reason for discordance was interpretation error (60%) followed by sampling error (20%) and technical errors (20%).

Conclusion: Accurate intra operative diagnosis depends on availability of relevant clinical information, skillful technical staff, expertise of the pathologist and comprehensive knowledge of pathological entities, indications and limitations of frozen section to avoid misinterpretation.

Key Words: Frozen section, Sampling error, Quality control, Diagnosis, Sensitivity, Specificity.