What does the Low-Density Lipoprotein Cholesterol test measure?

Why is Low-Density Lipoprotein Cholesterol measured?

LDL cholesterol is the primary lipid target in cardiovascular risk assessment and management and is the most extensively validated modifiable risk factor for atherosclerotic cardiovascular disease (ASCVD). Elevated LDL-C drives endothelial dysfunction, subendothelial lipoprotein deposition, macrophage foam cell formation, and atherosclerotic plaque development through both direct and oxidative mechanisms. A causal relationship between LDL-C and ASCVD is established through Mendelian randomisation studies, statin trials, and familial hypercholesterolaemia cohort data. LDL-C is used to stratify cardiovascular risk, guide lipid-lowering therapy initiation and titration, and monitor treatment response — with lower achieved LDL-C consistently associated with greater reduction in major adverse cardiovascular events across the evidence base.

Reference ranges

Standard reference

Optimal: <100 mg/dL (<2.59 mmol/L); Near optimal: 100–129 mg/dL; Borderline high: 130–159 mg/dL; High: 160–189 mg/dL; Very high: ≥190 mg/dL (≥4.91 mmol/L). # REVIEWER FLAG: LDL-C risk thresholds are stratified by individual cardiovascular risk, not absolute value alone — the above categories reflect NCEP ATP III/ACC/AHA population descriptors. Confirm LabCorp reporting format and whether they report a single numerical value with flagging or apply categorical labelling. Treatment targets differ by risk category (e.g., <70 mg/dL for very high-risk patients, <55 mg/dL in some ESC guidelines) and should be documented separately from the analytical reference range.

Functional medicine optimal

Functional medicine and preventive cardiology practitioners frequently target LDL-C below 70 mg/dL (<1.81 mmol/L) in patients with any cardiovascular risk factors, and below 55 mg/dL (<1.42 mmol/L) in patients with established ASCVD or very high risk — consistent with 2019 ESC/EAS guidelines. Some integrative practitioners also assess LDL particle number (LDL-P) and ApoB as more direct atherogenic burden markers when LDL-C appears discordant with overall lipid pattern. # REVIEWER FLAG: Optimal range targets are risk-stratified and guideline-dependent — ACC/AHA 2018 and ESC/EAS 2019 targets differ for very high-risk patients. Reviewer to confirm which guideline framework is most appropriate for the platform's practitioner audience and whether risk-stratified target tiers should be documented.

Units

mg/dL, mmol/L

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.