What laboratory tests are necessary for a general adult population in a primary care setting?

Laboratory Tests for General Adult Population in Primary Care

For healthy adults without risk factors in primary care, routine screening bloodwork should be minimal and age-based: lipid screening beginning at age 40, diabetes screening (A1C or fasting glucose) starting at age 45 or age 40-70 if BMI ≥25 kg/m², and blood pressure checks annually. 1, 2

Age-Stratified Screening Approach

Adults Under Age 40

• No routine laboratory screening is recommended for healthy adults under 40 without risk factors 1
• Lipid screening should only be performed if risk factors are present (diabetes, family history of premature cardiovascular disease, tobacco use, hypertension, or obesity) 1
• Blood pressure measurement annually remains the only universal screening 3

Adults Age 40-75

• Lipid profile (total cholesterol, HDL, LDL, triglycerides) should be obtained at age 40 and every 5 years thereafter if normal 1
• A1C or fasting glucose screening for diabetes beginning at age 45, or earlier (age 40-70) if BMI ≥25 kg/m² 1, 2
• Shorter screening intervals (every 1-3 years) are appropriate for those with lipid levels approaching treatment thresholds 1

Adults Age 50 and Older

• Continue lipid screening every 5 years 1
• Colorectal cancer screening beginning at age 50 in average-risk patients 4
• Annual mammography for women age ≥50 years 4
• Annual cervical Pap smear for women (after two normal tests in the first year following any diagnosis) 4

Risk Factors That Trigger Earlier/More Frequent Screening

The following risk factors warrant lipid and diabetes screening starting at age 20: 1

• Diabetes (for lipid screening)
• Family history of cardiovascular disease before age 50 in male relatives or age 60 in female relatives
• Multiple coronary heart disease risk factors (tobacco use, hypertension)
• Obesity

Technical Considerations for Lipid Testing

• Total cholesterol and HDL can be measured non-fasting, making screening more convenient 1
• Abnormal results must be confirmed with a repeated sample on a separate occasion, and the average of both results should guide treatment decisions 1
• A standard fasting lipid profile should include total cholesterol, HDL, triglycerides, and calculated or measured LDL 1
• Advanced lipoprotein testing beyond standard lipid profile is not recommended for cardiovascular risk assessment in asymptomatic adults 1

Common Pitfalls to Avoid

• Do not screen all young adults routinely regardless of risk factors—this leads to unnecessary testing and potential false positives 1, 2
• Never rely on a single lipid measurement for diagnosis or treatment decisions; always confirm abnormal results 1
• Do not order "routine annual labs" in healthy adults under 40 without specific clinical indications—this is not evidence-based 1
• Avoid universal A1C screening in adolescents; only screen those ≥10 years old with obesity/overweight AND additional risk factors 2

Special Population Considerations

Geriatric Patients (Age 65+)

For older adults, particularly those with chronic conditions, annual comprehensive laboratory testing is appropriate and should include: 3

• Complete blood count (CBC) with differential
• Comprehensive metabolic panel (CMP)
• Lipid profile
• Hemoglobin A1C
• Urinalysis with albumin-to-creatinine ratio
• Thyroid-stimulating hormone (TSH)
• Prostate-specific antigen (PSA) for men age 50+

Patients with Specific Conditions

The evidence provided focuses on disease-specific screening (breast cancer survivors, Alzheimer's disease, HIV) rather than general primary care populations 4. These specialized guidelines should not be extrapolated to healthy adults without those conditions.