Lab marker

LDL Cholesterol

LDL ("bad") cholesterol is the cholesterol fraction most directly tied to atherosclerotic cardiovascular disease risk.

Common unit mg/dL
Adult reference range Optimal <100 mg/dL; <70 mg/dL for very-high-risk patients

What it measures

Low-density lipoprotein cholesterol is the particle that deposits cholesterol into artery walls. Decades of randomised trials show that lowering LDL-C lowers the rate of heart attacks and strokes — the dose-response is one of the most reproduced findings in modern cardiology. Most clinical labs report LDL-C calculated from total cholesterol, HDL and triglycerides (the Friedewald equation), with direct measurement reserved for high-triglyceride states.

What a high value can mean

  • Atherogenic burden — every 1 mmol/L (38.7 mg/dL) reduction lowers major vascular events by ~22%.
  • Familial hypercholesterolaemia — values >190 mg/dL without lifestyle cause warrant genetic evaluation.
  • Dietary pattern — saturated fat and trans fat raise LDL more than dietary cholesterol does.
  • Hypothyroidism, nephrotic syndrome, cholestatic liver disease — secondary causes worth excluding.

What a low value can mean

  • Usually a benign or beneficial state — very low LDL is the goal in many secondary-prevention regimens.
  • Severe liver disease — impaired synthesis.
  • Hyperthyroidism — accelerated clearance.
  • Inflammation, malnutrition — transient drops.

When to discuss with a doctor

Risk-targeted thresholds (per ESC 2021 and AHA 2019): <100 mg/dL for low risk, <70 for high risk, <55 for very-high risk (prior heart attack, diabetes with target-organ damage, peripheral arterial disease). Mediora.AI plots your trajectory; lifestyle plus statin therapy decisions need a clinician who knows your full risk picture.

Related markers

See your own lab result explained marker-by-marker Upload a PDF or photo. Free during the open beta. Doctor-reviewed.
Upload →