Diagnostic Yield of Lipid Profile and Triglyceride Glucose Index in Differentiating Tuberculosis from Sarcoidosis

Purpose: Due to similar clinical, radiological, and pathological features, distinguishing tuberculosis (TB) from sarcoidosis can be challenging. We aimed to assess the significance of lipid levels and the triglyceride-glucose (TyG) index in differentiating TB from sarcoidosis. Methods: This retrospective observational study included 265 patients with newly diagnosed TB and 270 patients with sarcoidosis. Demographics and baseline levels of serum glucose, triglycerides (TG), total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and very-low-density lipoprotein (VLDL) were recorded. TyG indices were calculated separately. Data were compared between the TB and sarcoidosis groups using Chi-square and Student’s t-tests, and significant variables were assessed by logistic regression analysis. Discriminative ability was evaluated using receiver operating characteristic (ROC) analysis. Results: Males and younger individuals were more prevalent in TB (62% vs. 28%, p < 0.0001; 45.2 ± 17.1 vs. 48.8 ± 11.2 years, p = 0.004). Additionally, TG, total cholesterol, HDL, LDL, VLDL, and TyG index were significantly lower in the TB group (p < 0.0001 for all except HDL, where p = 0.001). Male sex, TG level, and TyG index were independent predictors for TB in logistic regression analysis. A cut-off value of 92.5 mg/dl for TG level predicted TB with 58% sensitivity and 80% specificity (AUC = 0.309, 95% CI 0.265-0.354). A cut-off value of 4.52 mg/dl for the TyG index predicted TB with 57% sensitivity and 80% specificity (AUC = 0.309, 95% CI = 0.265-0.354). Conclusion: TG level and TyG index appear to be hypothesis-generating biomarkers that may help explain metabolic differences between TB and sarcoidosis, rather than standalone diagnostic tools. Further prospective studies are warranted to clarify their potential adjunctive roles.