{"paper_id":"024bd87e-b689-4d9a-bdba-e3e5e0207282","body_text":"Abstract\nObjective To establish and validate reference intervals for the peripheral blood systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) in healthy children from the Zigong region of china.\nMethods A total of 2014 healthy children undergoing physical examination at The First People’s Hospital of Zigong from April 2023 to February 2025 were enrolled. Blood cell parameters were measured using the XN-1000 hematology analyzer, and SII, NLR, PLR, and LMR were calculated. The non-parametric method was employed to establish the 95% reference intervals.\nResults No statistically significant differences were observed in SII, NLR, PLR, or LMR between genders (P > 0.05). Participants were stratified into three age groups: 28 days to 2 years, 2 to 6 years, and 6 to 18 years. The established reference intervals for SII were 28.60×109/L to 298.85×109/L, 83.09×109/L to 601.33×109/L, and 140.02×109/L to 657.19×109/L, respectively, for the three age groups. The corresponding NLR reference intervals were 0.10-0.92, 0.35-1.88, and 0.57-2.30. PLR reference intervals were 29.39-115.15, 39.93-150.46, and 56.74-172.55. LMR reference intervals were 3.42-13.84, 2.81-13.03, and 2.41-10.56. A validation study conducted on 92 children from the Department of Child Health Care of the same hospital between April 2025 and September 2025 confirmed the applicability of these reference intervals. This indicates that the established reference intervals for peripheral blood SII, NLR, PLR, and LMR in children from the Zigong region are suitable for local clinical practice.\nConclusion This study is the first to establish reference intervals for NLR, PLR, SII, and LMR in children from the Zigong region, providing a basis for the assessment of inflammatory diseases in local pediatric populations.\nCompeting Interest Statement\nThe authors have declared no competing interest.\nFunding Statement\nYes\nAuthor Declarations\nI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.\nYes\nThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:\nThe study protocol was reviewed and approved by the Ethics Committee of The First People's Hospital of Zigong (NO.03202024).\nI confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.\nYes\nI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).\nYes\nI have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.\nYes\nData Availability Statement\nThe data supporting the findings of this study are available from the corresponding author upon reasonable request.","source_license":"CC-BY-4.0","license_restricted":false}