Which laboratory tests should be ordered for a routine health screening?

Routine Health Screening Laboratory Tests

For asymptomatic adults presenting for routine health screening, order targeted laboratory tests based on age-specific risk factors rather than comprehensive panels, as routine admission testing without clinical indication has minimal impact on patient care and generates more false positives than actionable findings.

Evidence-Based Approach to Test Selection

The evidence strongly demonstrates that indiscriminate laboratory testing in asymptomatic patients is not beneficial. Research shows that 45% of routine tests ordered without medical indication yield only 0.5% treatment changes, with most abnormal results representing physiologic or laboratory variation rather than disease 1. The key is to order tests based on specific screening guidelines for conditions where early detection improves outcomes, not comprehensive panels.

Recommended Age-Based Screening Tests

For Adults Age 45-50 and Older:

Diabetes Screening 2:

• Fasting plasma glucose (FPG) - preferred test due to ease, convenience, and lower cost
• Screen all adults ≥45 years
• Screen earlier if BMI ≥25 kg/m² PLUS any of:
  • Family history of diabetes
  • Physical inactivity
  • High-risk ethnicity (African-American, Hispanic, Native American, Asian-American, Pacific Islander)
  • History of gestational diabetes or baby >9 lbs
  • Hypertension (≥140/90 mmHg)
  • HDL <35 mg/dL or triglycerides >250 mg/dL
  • Polycystic ovary syndrome
  • History of vascular disease

Lipid Screening:

• Total cholesterol and triglycerides
• Identifies hyperlipidemia (total cholesterol >230 mg/dL or triglycerides >250 mg/dL) 3

Colorectal Cancer Screening (starting age 50) 4:

• Annual fecal immunochemical test (FIT) OR
• Annual guaiac-based fecal occult blood test (gFOBT) with high sensitivity

Condition-Specific Testing:

Only order additional tests when clinical indicators are present 3, 1:

• Complete blood count: Only if symptoms suggest anemia, infection, or hematologic disorder
• Comprehensive metabolic panel: Only if symptoms suggest renal, hepatic, or electrolyte abnormalities
• Liver enzymes: Only with risk factors for liver disease (not as routine screening due to 38-59% of abnormal results having unclear significance) 3
• Renal function (creatinine, BUN): Only with hypertension, diabetes, or symptoms of renal disease

Critical Pitfalls to Avoid

1. Do not order comprehensive metabolic panels routinely - The most frequent cause of abnormal results in asymptomatic patients is physiologic or laboratory variation, not disease 5

2. Avoid "routine admission" or "wellness panel" approaches - These generate unnecessary follow-up testing without improving mortality or cardiovascular outcomes 6

3. Do not pursue extensive workup for isolated abnormalities without clinical correlation - In the absence of signs or symptoms correlating with an abnormal screening test, follow-up testing is usually unnecessary 5

What General Health Checks Actually Accomplish

While general health checks don't reduce mortality or cardiovascular events, they do improve 6:

• Detection and control of hypertension and cholesterol
• Uptake of age-appropriate cancer screening
• Recognition of depression (5% vs 2% new antidepressant prescriptions)
• Patient-reported quality of life

The value lies in facilitating guideline-based preventive services, not in comprehensive laboratory testing.