What blood work screenings are recommended for an 18-year-old with no prior medical history?

Blood Work Screenings for 18-Year-Olds

For an 18-year-old with no prior medical history, routine blood work screening should be limited to blood pressure measurement only, with additional testing reserved for those with specific risk factors such as elevated BMI or sexual activity. 1

Universal Screening Recommended at Age 18

Blood Pressure Screening

• Screen blood pressure universally starting at age 18, as this is a Grade A recommendation from the USPSTF with high certainty of substantial net benefit 2, 3
• Measure blood pressure every 2 years if <120/80 mm Hg 2, 1
• Measure annually if systolic BP is 120-139 mm Hg or diastolic BP is 80-89 mm Hg 2
• This screening prevents premature death, myocardial infarction, renal insufficiency, and stroke 2, 1

Risk-Based Laboratory Screening at Age 18

Diabetes Screening

• Do not perform routine hemoglobin A1C or glucose testing unless the patient has BMI ≥25 kg/m² with additional risk factors 1
• The USPSTF found insufficient evidence to recommend universal diabetes screening in youth under 18, and this extends to low-risk 18-year-olds 4

Lipid Screening

• Routine cholesterol testing should begin at age 20, not 18, according to ATP III guidelines 2
• The exception is if there is family history of premature cardiovascular disease (≤55 years of age) or parental hypercholesterolemia 2

Anemia Screening

• Do not perform routine CBC or hemoglobin testing unless specific risk factors are present 1
• Risk factors warranting screening include heavy menstrual bleeding, restrictive diets, or chronic disease 1

Mental Health and Behavioral Screening (Non-Laboratory)

Depression Screening

• Screen annually for depression from age 11 through 21, as suicide is a leading cause of death in this age group 1

Substance Use Screening

• Use the CRAFFT screening questionnaire to assess alcohol and drug use, as structured approaches improve detection rates 1, 5

Sexual Health Screening

• Screen for HIV infection at ages 16-18 years, particularly given that one in four new HIV infections occurs in persons aged 13-24 years 1
• Perform sexually transmitted infection screening based on sexual activity and risk assessment 1

What NOT to Screen at Age 18

Cervical Cancer Screening

• Do not screen for cervical dysplasia until age 21, regardless of sexual activity 1
• This represents an important shift from previous recommendations that started screening earlier 1

Vision Screening

• Transition to risk-based vision assessment rather than routine screening at age 18 1
• Universal visual acuity screening is not necessary unless risk factors are present 1

Comprehensive Metabolic Panels

• Do not perform routine CMP, liver function tests, or kidney function tests in healthy 18-year-olds without risk factors 1
• These recommendations for annual comprehensive metabolic panels apply to adults aged 18-39 years with risk factors, not universally 6, 7

Common Pitfalls to Avoid

• Avoid over-screening for conditions without evidence-based recommendations at this age, such as routine lipid panels in low-risk individuals 1
• Do not rely on passive questioning for behavioral health risks—use validated screening tools 1
• Recognize that general health checks with extensive laboratory panels have not been shown to reduce morbidity or mortality in unselected populations 8
• The increased number of diagnoses from broad screening may lead to overdiagnosis and unnecessary follow-up procedures without improving health outcomes 8

Clinical Context

The evidence strongly supports a targeted, risk-based approach to laboratory screening at age 18 rather than comprehensive panels. While some practice guidelines suggest annual CBC and CMP for adults 18-39 years 6, 7, these recommendations lack strong evidence for universal application in truly healthy 18-year-olds. The USPSTF blood pressure screening recommendation stands as the only Grade A universal screening at this age 2, 3. Additional laboratory testing should be driven by specific risk factors, family history, or clinical findings rather than age alone 1.