Routine Laboratory Tests and Screenings for an 18-Year-Old Male
For an otherwise healthy 18-year-old male without specific risk factors, routine laboratory testing and comprehensive physical examinations are not recommended, as they have minimal yield in detecting significant pathology and are not cost-effective. 1
Blood Pressure Screening
- Annual blood pressure measurement is the single most important screening test for this age group and should be performed using proper technique. 2
- This is the only universally recommended screening for healthy young adults in this age category.
Risk-Based Laboratory Testing
Sexually Transmitted Infection Screening
- If sexually active with multiple partners or new partners, annual screening for syphilis (RPR or VDRL), gonorrhea, and chlamydia is indicated. 2
- Testing should be performed based on sexual history and risk behaviors, not as routine screening in asymptomatic patients without risk factors.
Hepatitis Screening
- Hepatitis B (HBsAg, HBsAb, anti-HBc) and hepatitis C antibody testing should only be performed if specific risk factors are present, including injection drug use, multiple sexual partners, or occupational exposure. 2
Metabolic Screening
- Diabetes screening with HbA1c, fasting plasma glucose, or 2-hour OGTT is not recommended until age 35 years unless the patient has risk factors such as BMI ≥25 kg/m², family history of diabetes, or other metabolic syndrome components. 2
- Lipid panel screening is not routinely indicated at age 18 in the absence of cardiovascular risk factors or strong family history of premature cardiovascular disease. 2
What NOT to Do
Avoid Routine "Complete Physical Examinations"
- Comprehensive annual physical examinations in adolescents and young adults have practically no value in finding important pathologic conditions. 1
- In a review of over 20,000 routine examinations of adolescents, only 2 had major previously unknown findings. 1
- The most frequent cause of abnormal screening test results in healthy patients is physiologic or laboratory variation, not underlying disease. 3
Avoid Routine Laboratory Panels
- Do not order screening CBC, comprehensive metabolic panel, urinalysis, or thyroid function tests in asymptomatic 18-year-old males without clinical suspicion of disease. 3, 1
- These tests have poor predictive value in healthy young adults and lead to unnecessary follow-up testing for false-positive results.
Important Clinical Caveats
The key principle is that laboratory testing should be ordered to confirm diagnostic suspicions raised during history-taking, not as blanket screening. 3 When abnormal results are obtained from screening tests ordered without diagnostic suspicion, the physician should search for correlating signs and symptoms before pursuing further testing. 3
For sexually active teenagers, the approach differs significantly – targeted screening for STIs becomes appropriate based on sexual history and risk behaviors. 2
Family history assessment is critical as it may identify need for earlier screening for conditions like diabetes, cardiovascular disease, or hereditary cancer syndromes. 2 For example, patients with Peutz-Jeghers syndrome require extensive surveillance starting at age 18, including colonoscopy and upper endoscopy every 2-3 years. 4