Lipid Panel & Ratios

Statins (atorvastatin, rosuvastatin) lower LDL and total cholesterol substantially, and can slightly raise HDL. Your unmedicated lipid profile would likely show higher LDL and TC values.

Fibrates (fenofibrate, gemfibrozil) lower triglycerides and can raise HDL. They have a smaller effect on LDL than statins.

Niacin (high-dose B3) raises HDL and lowers triglycerides. It can modestly raise blood glucose, so interpretation alongside HbA1c and fasting glucose matters.

Hormone therapy (estrogen-based) can raise HDL and triglycerides. Testosterone therapy can lower HDL. Both alter the ratios meaningfully.

Corticosteroids (prednisone, dexamethasone) raise triglycerides and total cholesterol while lowering HDL — typically worsening all three ratios.

If you are on any of these medications, your ratios reflect the medicated state. Discuss trends and underlying baseline with your provider.

Formula

TC:HDL = Total Cholesterol ÷ HDL. LDL:HDL = LDL ÷ HDL. TG:HDL = Triglycerides ÷ HDL. Both numerator and denominator are converted to mg/dL before division so the ratios are consistent regardless of input units. Cholesterol mmol/L × 38.67 → mg/dL; Triglycerides mmol/L × 88.57 → mg/dL.

Ratio Thresholds

TC : HDL <3.5 Optimal / 3.5–5.0 Borderline / ≥5.0 Elevated risk

LDL : HDL <2.5 Optimal / 2.5–3.5 Borderline / ≥3.5 Elevated risk

TG : HDL <2.0 Optimal / 2.0–3.0 Borderline / ≥3.0 Elevated — insulin resistance signal

Limitations

Lab values vary day-to-day with hydration, recent meals, exercise, illness, and medication timing. Triglycerides especially are highly sensitive to recent meals — fasting samples only. Standard reference ranges (the lab 'normal') are derived from average populations, which include many people with metabolic dysfunction. Optimal ranges may be tighter than reference ranges. Trends over multiple measurements are more reliable than any single reading.

Sources

Castelli WP, Cardiology Clinics, 1996 (TC:HDL). Millán J et al., Lipoprotein ratios: physiological significance and clinical usefulness in cardiovascular prevention, Vascular Health and Risk Management, 2009. McLaughlin T et al., Use of metabolic markers to identify overweight individuals who are insulin resistant, Annals of Internal Medicine, 2003 (TG:HDL).