Correspondence to Point-of-care blood eosinophil counts used to predict wheezing episodes in preschool childrenYangyang Tong11Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Changsha, China.Correspondence :Yangyang Tong(226511101@csu.edu.cn)Funding: The authors received no specific funding for this work.Dear Editor,I am writing to provide my comments on the article Point-of-care blood eosinophil counts used to predict wheezing episodes in preschool children by Hillson et al. 1 Although this study provides valuable applications of Point-of-care blood eosinophil counts for predicting wheezing episodes, several aspects of the study warrant further discussion.Regional, genetic, and sex factors are not fully considered in this paper. Among the 73 subjects, 74% of the children are from the same region and Caucasian, and about two-thirds are male, making the analysis of other ethnic backgrounds and genders inadequate.Environmental and genetic factors, childhood morbidity, diet and exercise, underlying medical history,and treatment strategies may influence eosinophil counts and wheezing episodes.Therefore, it is advisable to broaden the study sample to include children from diverse regions and ethnic and socioeconomic backgrounds to enhance the external validity of the findings.Although the children in the study are tested for allergens and diagnosed with wheezing, it is recommended to increase screening for other potential comorbidities, such as bronchomalacia, other immune diseases, etc., to control for potential effects on the study results.2 The authors recruit children with a diagnosis of recurrent wheezing and focused on the population with allergic wheezing. The effect of different treatment regimens on blood eosinophil counts (BEC) remains unclear. In particular, the effect of montelukast or other drugs on BEC and the number of wheezing episodes was studied. Of note, unlike ICS and LABAs, oral prednisolone is not appropriate for long-term use, so the effects of these agents should be more thoroughly evaluated, especially in preschool-age children.Another problem is that wheezing episodes are variable and inconsistent, and some wheezing episodes may be diagnosed only by stethoscope, which can lead to variability in diagnosis, especially in mild or intermittent cases. 3 To reduce subjective bias in filling out the TRACK questionnaire, it is recommended that guardians receive standardized training before conducting the survey to improve the identification of mild cases.On the premise of ensuring follow-up and test compliance, single-point verification BEC may need to be improved and the frequency may be increased, such as 3 weeks, 3 months, and 12 months.4The discussion of the socioeconomic impact of POC devices is more limited in this paper. The costs of purchasing, maintaining, and adjusting POC devices, their value for use at different levels of care, especially their economic viability in low-income populations, remain of interest, in addition to the fact that this study used only one POC device and a single decision tree model. It is suggested that other machine learning models, such as support vector machine (SVM) models, should be combined in the future research, and multiple features such as BEC, symptom score, and lung function should be included in the comprehensive evaluation, and the prediction accuracy should be improved through cross validation.5 In the future, we will further investigate potential environmental exposure and socioeconomic factors, consider the universality of POC devices diversity , expand the sample size, Multi-point validation of BEC and through multi-center trials, and extend the follow-up time to 12 months to explore its impact on the long-term disease course, so as to provide more comprehensive data.6In conclusion, this paper makes an important contribution to advancing the early diagnosis and management of wheezing in preschool children. By addressing the methodological issues described above, the clinical validity of BEC testing with POC devices as a predictor of future wheezing episodes will be more strongly supported. Developing guidelines for risk monitoring and management of different wheezing diagnosis and treatment options will be an important direction for future research.Word count: 590