<![CDATA[Background: In the era of personalized medicine, biomarkers have become an important tool for detecting and predicting asthma episodes over the last decade, one of them is urinary bromotyrosine. It has several advantages as a potential biomarker for asthma, including its stability and the practicality of noninvasive urine sampling. Therefore, this study aims to investigate further the role of urinary bromotyrosine levels and their correlation with eosinophil levels in asthma patients. Methods: This is an analytical observational study with a cross-sectional design. From May to December 2023, the study involved 82 patients from the Harum Melati Clinic in Pringsewu, Lampung, Indonesia. The participants underwent spirometry, differential leukocyte count, urinalysis, and chest X-rays. The severity of asthma obstruction was classified into asthmatic (n=72) as the case group, with non-asthmatic patients (n=10) serving as the control group. Urinary bromotyrosine levels were tested using the 3-BrY ELISA Kit EU3112. Results: Urinary bromotyrosine levels were significantly higher in asthma patients compared to the non-asthma group (154.11 ng/mL vs. 11.87 ng/mL; P=0.0001). Furthermore, elevated eosinophil levels in asthma patients showed a strong correlation coefficient (0.307) with higher urinary bromotyrosine levels, indicating statistical significance (P=0.005). Conclusion: This study found a significant difference in urinary bromotyrosine levels between asthmatic and non-asthmatic participants. There was a strong correlation between elevated eosinophil counts in patients with asthma and increased urinary bromotyrosine levels.]]>
