TITLE:
Assessment and Comparison of the Efficacy of Clove Oil versus Xylene as a Deparaffinizing and Clearing Agent during Hematoxylin and Eosin Staining at Muhimbili National Hospital Dar es Salaam, Tanzania
AUTHORS:
Ussi Hamza Ussi, Nujaima Said, Amos Rodger Mwakigonja, Jesca William, Mohamedi Mnyamulu, Zekai Lin, Tasnim Thabit
KEYWORDS:
Clove Oil, Xylene, H&E Staining, Deparaffinizing Agent, Clearing Agent, Histopathology
JOURNAL NAME:
Journal of Biosciences and Medicines,
Vol.14 No.3,
March
18,
2026
ABSTRACT: Introduction: Xylene is used as a clearing and deparaffinizing agent during haematoxylin and eosin (H&E) staining in histopathology laboratories. However, in addition to its expensive cost, the risks of xylene exposure are concerning. These risks include flammability, carcinogenicity, and allergic reactions. Many alternatives have been considered as possible replacements, including essential oils. Clove oil, which is widely accessible in Zanzibar, could provide a more affordable and practical substitute. Aim: The aim of this study is to evaluate and contrast the deparaffinizing and clearing properties of clove oil and xylene in the course of routine H&E staining at Muhimbili National Hospital. Study Design: A prospective, comparative, matched-pairs experimental laboratory design. Setting: Muhimbili National Hospital, Central Pathology Laboratory, Dar es Salaam, Tanzania. Methodology: During the (February-June 2023) research period, 23 routine biopsy specimens were collected. 23 matched pairs (46 separate tissue samples) were created by splitting each specimen in half. During H&E staining, one half of each pair was processed with xylene as the deparaffinizing and clearing agent (Group A), whereas the other half was processed with clove oil (Group B). A pathologist who was blind to the clearing chemical employed reviewed each slide at random. Staining quality was evaluated using a standardized binary scoring system for four parameters: background clarity, nuclear staining preservation, cytoplasmic staining preservation, and dewaxing efficacy. McNemar’s test was used to analyze the data with 95% confidence intervals for paired proportions. Results: For all parameters, including dewaxing [23/23 (100%) vs. 18/23 (78.3%)], nuclear staining [23/23 (100%) vs. 20/23 (87.0%)], cytoplasmic staining [23/23 (100%) vs. 19/23 (82.6%)], and background clearing [23/23 (100%) vs. 20/23 (87.0%)], xylene showed greater percentages of successful outcomes than clove oil. McNemar’s test revealed no statistically significant differences between xylene and clove oil for background clearing (p = 0.2500), cytoplasmic staining (p = 0.1250), or nuclear staining (p = 0.2500). For dewaxing, there was a trend toward significance (p = 0.0625). Nuclear staining was 13.0% (−4.5% to 30.1%), cytoplasmic staining was 17.4% (−2.3% to 35.3%), background staining was 13.0% (−4.5% to 30.1%), and dewaxing was 21.7% (0.5% to 40.2%) with 95% confidence intervals. Conclusion: Clove oil can perform similarly to xylene in the deparaffinization and clearing stages of standard H&E staining in terms of background clarity, nuclear staining preservation, cytoplasmic staining quality, and dewaxing efficacy.