What are the normal values for triglycerides and cholesterol levels?

Normal Triglyceride and Cholesterol Values

Normal triglyceride levels should be below 150 mg/dL, while total cholesterol should be below 190 mg/dL for adults, with LDL cholesterol below 100-130 mg/dL (depending on cardiovascular risk) and HDL cholesterol above 40 mg/dL for men and above 50 mg/dL for women. 1, 2

Standard Lipid Profile Reference Ranges

Triglycerides

• Normal/Desirable: <150 mg/dL
• Borderline-high: 150-199 mg/dL
• High: 200-499 mg/dL
• Very high: ≥500 mg/dL 1

Total Cholesterol

• Acceptable: <190 mg/dL
• Borderline-high: 190-224 mg/dL
• High: ≥225 mg/dL 1, 2

LDL Cholesterol

• Optimal: <100 mg/dL
• Near optimal/Above optimal: 100-129 mg/dL
• Borderline-high: 130-159 mg/dL
• High: ≥160 mg/dL 1, 2

HDL Cholesterol

• Low (risk factor): <40 mg/dL for men, <50 mg/dL for women
• Acceptable: ≥45 mg/dL
• Optimal/Protective: ≥60 mg/dL 1, 2

Non-HDL Cholesterol

• Optimal: <130 mg/dL
• Borderline-high: 150-189 mg/dL
• High: ≥190 mg/dL 1, 2

Risk Stratification and Target Values

The American Heart Association and other major cardiovascular societies recommend different target values based on cardiovascular risk:

Very High-Risk Patients

• LDL-C goal: <70 mg/dL
• These include patients with established cardiovascular disease, diabetes with target organ damage, or a 10-year risk score ≥10% 2

High-Risk Patients

• LDL-C goal: <100 mg/dL
• These include patients with significant risk factors, diabetes without target organ damage 1, 2

Moderate-Risk Patients

• LDL-C goal: <130 mg/dL
• These include patients with 2+ risk factors with 10-year risk 10-20% 2

Low-Risk Patients

• LDL-C goal: <160 mg/dL
• These include patients with 0-1 risk factor 2

Clinical Implications

Triglyceride levels ≥500 mg/dL significantly increase the risk of pancreatitis and require immediate intervention 1. Levels between 200-499 mg/dL are associated with increased cardiovascular risk and often occur alongside low HDL cholesterol, particularly in patients with metabolic syndrome or diabetes 1.

The prevalence of hypertriglyceridemia (≥150 mg/dL) in the United States is approximately 31% of the adult population 1, 3. Among statin-treated adults, this prevalence increases to 31.6%, representing about 12.3 million Americans 3.

Measurement Considerations

• Total cholesterol levels can be measured at any time of day in non-fasting patients as they don't vary appreciably with eating 1
• A fasting lipid profile (nothing to eat or drink except water for 12 hours) provides more complete information, especially for triglycerides and calculated LDL cholesterol 1
• LDL cholesterol is typically calculated using the Friedewald formula: LDL-C = Total-C - (HDL-C + [Triglycerides/5]) 1
• This formula becomes less accurate when triglycerides exceed 400 mg/dL 1

When abnormal values are detected, it's recommended to repeat the test and consider the average value for clinical decision-making 1.

Common Pitfalls and Caveats

1. Calculation limitations: The standard Friedewald formula for calculating LDL-C becomes inaccurate when triglycerides exceed 400 mg/dL 1

2. Variability in measurements: Triglyceride levels show high variability and are significantly affected by recent food intake, requiring fasting samples for accurate assessment 4

3. Focus on LDL alone: Overemphasizing LDL cholesterol at the expense of other lipid parameters (HDL, triglycerides) may miss important cardiovascular risk factors 5

4. Overlooking non-HDL cholesterol: Non-HDL cholesterol (total cholesterol minus HDL cholesterol) is an important risk marker that includes all potentially atherogenic lipoproteins 1

5. Ethnic variations: Significant differences exist in lipid profiles across ethnic groups, with Mexican Americans having the highest rates of hypertriglyceridemia (34.9%), followed by non-Hispanic whites (33%) and blacks (15.6%) 1