What is a lipid test called?

Lipid Test: Types and Components

A lipid test, commonly known as a lipid profile or lipid panel, is a blood test that measures various types of fats (lipids) in your blood to assess cardiovascular risk. 1, 2

Components of a Standard Lipid Profile

• Total Cholesterol (TC): Measures all cholesterol in the blood, including both LDL and HDL cholesterol 1, 2
• Low-Density Lipoprotein Cholesterol (LDL-C): Often called "bad cholesterol" as it contributes to plaque buildup in arteries 1, 3
• High-Density Lipoprotein Cholesterol (HDL-C): Known as "good cholesterol" because it helps remove other forms of cholesterol from the bloodstream 1, 3
• Triglycerides (TG): A type of fat in the blood that can increase risk of heart disease when elevated 1, 3
• Non-HDL Cholesterol: Calculated as Total Cholesterol minus HDL Cholesterol; represents all atherogenic lipoproteins 2, 4

Fasting vs. Non-fasting Testing

• Traditionally, lipid profiles required 9-12 hours of fasting 1, 5
• Current guidelines support non-fasting lipid profiles for routine cardiovascular risk assessment 1, 4
• Non-fasting lipid profiles show minimal clinically significant differences compared to fasting tests:
  • Triglycerides may be up to 20% higher 1, 5
  • LDL-C may be about 10% lower 1, 4
  • Total cholesterol and HDL-C show minimal changes 5, 4
• Fasting is still recommended in specific situations:
  • When triglycerides are >400 mg/dL (>4.5 mmol/L), as the Friedewald equation for calculating LDL-C becomes inaccurate 1
  • When specifically monitoring triglyceride levels 1

Advanced Lipid Testing

• Apolipoprotein B (ApoB): A direct measure of LDL particle numbers; each LDL particle contains one ApoB molecule 1, 6
• Apolipoprotein A (ApoA): Associated with HDL particles but less directly than ApoB is with LDL 1, 6
• Lipoprotein(a) [Lp(a)]: A large glycoprotein attached to an LDL-like particle; associated with increased cardiovascular risk 1, 2
• LDL particle number and size: Can be measured through specialized techniques 1, 7

Clinical Application

• The standard lipid profile is sufficient for cardiovascular risk assessment in most patients 1, 2
• Advanced lipid testing generally provides little additional predictive value beyond standard lipid measurements for most patients 1
• In children and adolescents with diabetes, initial lipid profile should be performed after diagnosis (preferably after glycemia has improved) and when age is ≥2 years 1
• For screening purposes, non-fasting lipid profiles are preferred due to:
  • Greater convenience for patients 1, 5
  • Reduced burden on laboratories 1, 5
  • Minimized risk of hypoglycemia in diabetic patients 5, 4

Interpretation Considerations

• Diagnosis of dyslipidemia should not be based on a single measurement due to intraindividual variability 3, 6
• For adequate risk assessment, at least HDL-C and LDL-C should be analyzed, especially in women and in subjects with diabetes or metabolic syndrome 1, 3
• The Friedewald formula is commonly used to calculate LDL-C when triglycerides are <400 mg/dL: LDL-C = TC - HDL-C - (TG/5) in mg/dL 1

Monitoring Considerations

• Routine monitoring of lipids after initiating statin therapy is generally not recommended as efficacy is based on target dose, not lipid levels 1
• Lipid testing may be reasonable to assess adherence to therapy or when using high-dose statins 1
• Baseline liver function tests and creatine kinase levels are clinically prudent before initiating statin therapy 1