Diagnostic value of neutrophil-to-lymphocyte, platelet-to-lymphocyte, and lymphocyte-to-monocyte ratios for assessing organ and multiorgan involvement in sarcoidosis: a retrospective single-center study

Background Sarcoidosis is a heterogeneous disease lacking reliable biomarkers for organ involvement. Indices derived from the complete blood count (CBC), including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR), have emerged as accessible markers of systemic inflammation. Objectives To assess whether CBC parameters and NLR, PLR, and LMR vary across demographic and clinical features in sarcoidosis, and to evaluate their diagnostic performance for organ-specific and multiorgan involvement. Methods A retrospective, single-center observational study included adults with sarcoidosis diagnosed between 2000 and 2025. Age- and sex-adjusted logistic regression evaluated associations between hematologic indices at diagnosis and organ involvement. Additional logistic regression using analytical parameters evaluated associations between blood count–derived ratios and multiorgan involvement. Firth’s correction was applied when the events-per-variable ratio was < 10, and analyses were repeated using log-transformed hematologic ratios when skewness coefficient > 2. Diagnostic performance was assessed by receiver operating characteristic (ROC) curve analysis. Results A total of 229 patients were included (mean age 51.34 years; 57.64% women). Median values for NLR, PLR, and LMR were 2.57, 158.97, and 3.17, respectively. Higher NLR and PLR were independently associated with extrathoracic lymph node involvement (NLR: OR = 13.42, 95% CI 1.91–94.32, p = 0.001, PLR: OR = 1.01, 95% CI 1.00–1.01, p = 0.008). NLR was associated with splenic involvement (OR = 83.05, 95% CI 6.75–1021.09, p = 0.001); Firth’s correction confirmed the association (OR = 23.72; 95% CI 7.53–74.70). Log-transformed NLR remained associated with splenic (OR = 2.74 per 10% increase, 95% CI 1.92–3.91) and extrathoracic lymph node involvement (OR = 2.17 per 10% increase, 95% CI 1.60–2.94). NLR was associated with multiorgan disease (OR = 24.60, 95% CI 5.90–102.00, p < 0.001), and log-transformed NLR showed a consistent association (OR = 2.13 per 10% increase, 95% CI 1.56–2.91). The area under the ROC curve was 0.51 for ≥2 organs, 0.69 for ≥3 organs, and 0.99 for ≥4 organs. Conclusion NLR was independently associated with multiorgan disease, splenic and extrathoracic lymph node involvement. PLR was independently associated with extrathoracic lymph node involvement.