Yes, draw a lipid profile on an 18-year-old
Universal screening is recommended once between ages 17-21 years, making an 18-year-old due for lipid assessment regardless of risk factors 1.
Screening Recommendation
The 2011 NHLBI Expert Panel guidelines explicitly recommend universal screening for all individuals aged 17-21 years (Grade B recommendation) 1. This represents a shift from the 12-16 year age group where routine screening is not recommended due to decreased sensitivity and increased false-negative results during puberty.
What to Order
You have two options for the 18-year-old:
Option 1: Non-fasting lipid panel (more practical)
- Calculate non-HDL cholesterol (Total cholesterol - HDL cholesterol)
- If non-HDL ≥145 mg/dL or HDL <40 mg/dL: obtain fasting lipid profile twice and average the results 1
Option 2: Fasting lipid panel
- If any of the following are abnormal, repeat fasting lipid profile and average results 1:
- LDL cholesterol ≥130 mg/dL
- Non-HDL cholesterol ≥145 mg/dL
- HDL cholesterol <40 mg/dL
- Triglycerides ≥130 mg/dL
Practical Considerations
Non-fasting is preferred for initial screening in this age group because:
- Better patient compliance (no need to fast)
- Minimal clinical difference in lipid values after normal meals (maximal changes: triglycerides +26 mg/dL, total cholesterol -8 mg/dL, LDL -8 mg/dL) 2, 3
- Non-fasting samples predict cardiovascular risk equally well as fasting 3
Common Pitfall
Do not skip screening in healthy 18-year-olds thinking they are "low risk." The guideline specifically mandates universal screening in this age bracket to identify familial dyslipidemias and establish baseline cardiovascular risk early 1. Early identification allows for lifestyle intervention during a critical period before atherosclerotic disease develops.
When to Obtain Fasting Sample
Reserve fasting lipid panels for:
- Abnormal non-fasting results requiring confirmation
- Triglycerides >440 mg/dL on non-fasting sample 2
- Known or suspected genetic dyslipidemia requiring precise diagnosis