TyG Index Calculator (Triglyceride-Glucose Index)
Triglyceride-glucose (TyG) index as a surrogate for insulin resistance — ln(TG × glucose ÷ 2) — with cut-offs, TyG-BMI and TyG-waist variants and comparison to HOMA-IR.
How it works
TyG = ln[ fasting triglycerides (mg/dL) × fasting glucose (mg/dL) ÷ 2 ]; mmol/L → mg/dL: TG × 88.57, glucose × 18
Insulin resistance is usually estimated with HOMA-IR, which needs a fasting insulin assay that many laboratories do not run and that is poorly standardised. The triglyceride-glucose index sidesteps that: insulin-resistant liver and fat tissue release more triglyceride-rich lipoproteins and fail to suppress glucose output, so the product of the two fasting values tracks insulin resistance closely — in validation against the euglycaemic clamp it performed as well as or better than HOMA-IR. It is dimensionless, cheap and available from any standard lipid and glucose panel. Large cohorts link higher TyG to incident diabetes, fatty liver, hypertension and cardiovascular events. Cut-offs are population-specific; 8.5 to 8.8 is the range most often quoted for “elevated”, and multiplying by BMI or waist circumference improves discrimination.
Worked example
Triglycerides 165 mg/dL and glucose 104: ln(165 × 104 / 2) = ln(8,580) = 9.06 — elevated, consistent with insulin resistance; with BMI 29.4 the TyG-BMI is 266.
Frequently asked questions
How does TyG compare to HOMA-IR numerically?
They are different scales. Roughly, TyG 8.5–8.8 corresponds to HOMA-IR around 2.5 in many studies, but correlation is moderate (r ≈ 0.3–0.5) and neither is a diagnostic test.
Can I use non-fasting values?
No — both triglycerides and glucose rise after meals, which would inflate the index. Use an 8–12 hour fasting sample.
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Clinical decision tool for education and for use by trained clinicians alongside judgement — not a diagnosis and not a substitute for medical assessment. Scores validated in specific populations may not apply to every patient.