Pathology

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http://etd.aau.edu.et/handle/123456789/67

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Browsing Pathology by Subject "Fixation, Formalin, Microwave, Slide quality, Duration of tissue fixation"

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    Performance Evaluation of Conventional Formalin Fixation and Rapid Microwave, Formalin Free Fixation of Large Biopsy Specimens
    (Addis Ababa University, 2018-10) Abite, Yeshwas; Gemechu, Tufa (MD, Pathologist, Associate professor)
    Background: Fixation is the first most important preparative technique. Formaldehyde causes a burning sensation to the eyes, nose, and lungs at high concentrations and also has possible associations with cancers of various organs in occupationally exposed populations. It takes about 24 hours for complete fixation. Microwave fixation method is an alternative tissue fixation technique which can decrease formalin exposure and fixation time. Objective: The objective of this study was to compare the quality of slides prepared by formalin and microwave fixation methods and to compare the time duration of the two methods. Materials and Methods: A prospective cross sectional study was conducted in Tikur Anbessa Specialized Hospital (TASH) from January 2017 to August 2018. A total of 120 paired tissue samples were collected by convenient type of sampling method. Domestic type of microwave and ten percent formalin were used for microwave and conventional fixation respectively. Chi square and kappa statistics were computed for association and agreement tests respectively. Results: Microwave fixation method reduced the time of fixation to 11 minutes while it was 24 hours in formalin fixation. According to observer I, 89.2% and 45% of slides prepared by formalin and microwave fixation methods respectively, gave at least satisfactory result. While as per observer II, 97.5% and 91.2% of the slides prepared by the two fixation methods respectively, gave the same result. The agreement between the two fixation methods on slide qualities was positive except for some parameters. The slide grade of 33 % and 17% of all types of tissue was significantly associated (p< 0.05) with fixation method according to observers I and II respectively. While the slide grades of the rest (67% and 83%) of slides were not dependent on methods of fixation according to these observers respectively.. Conclusion: Microwave irradiation under controlled conditions can reduce fixation time to 11 minutes without significant loss of specimen quality. It can also reduce staffs exposure to formalin. Further assessment need to be done before implementing these methods in various settings.