What laboratory tests and investigations are recommended for a preventive health assessment in a 47-year-old man who is a former smoker and currently uses electronic cigarettes (vaping)?

Recommended Laboratory Tests and Investigations for a 47-Year-Old Former Smoker Who Currently Vapes

This patient does not yet meet criteria for lung cancer screening with low-dose CT (LDCT), but should be counseled about smoking cessation including vaping cessation, and standard age-appropriate preventive health screening should be performed.

Lung Cancer Screening Assessment

Current Eligibility Status

Your 47-year-old patient does not qualify for lung cancer screening at this time based on current guidelines 1, 2. The most recent NCCN guidelines (2025) recommend LDCT screening for individuals who are:

• Age ≥50 years (Category 1 evidence)
• ≥20 pack-year smoking history (Category 1 evidence)
• No time limit after smoking cessation (the 15-year quit criterion has been eliminated) 2

Key Point: The patient needs to wait until age 50, at which point eligibility should be reassessed based on cumulative smoking history. The NCCN eliminated the "years since quitting" restriction in 2022 because lung cancer risk remains elevated well beyond 15 years after cessation 2.

Critical Smoking History Documentation

You must quantify:

• Pack-years: (cigarettes per day ÷ 20) × years smoked
• Current vaping status: Document as "current user" of electronic nicotine delivery systems 3
• Former cigarette smoking: Specify when quit and total duration
• Additional risk factors: Occupational exposures (asbestos, radon), family history of lung cancer in first-degree relatives, history of COPD or pulmonary fibrosis 4, 2

Vaping-Specific Assessment

Clinical History Elements

Document the following vaping details 5:

• Type of device: Disposable, cartridge-based, or tank system
• Frequency and duration: Days per week, duration of use
• Substance vaped: Nicotine concentration, presence of THC/CBD, flavoring types
• Symptoms: Respiratory symptoms (cough, dyspnea, chest pain), cardiovascular symptoms (palpitations, chest discomfort)

Laboratory and Diagnostic Tests

Baseline pulmonary function testing should be considered given vaping exposure:

• Spirometry: FEV₁, FVC, FEV₁/FVC ratio, FEF₂₅₋₇₅% 6
  • Acute vaping exposure decreases FEV₁, FVC, PEF, and MEF₇₅
  • Chronic exposure reduces FEV₁, PEF, FEV₁/FVC, and FEF₂₅₋₇₅%
• Fractional exhaled nitric oxide (FeNO): Can detect subclinical airway inflammation that spirometry misses 6
• Carboxyhemoglobin (HbCO) level: Elevated in chronic vapers 6

Important caveat: Standard spirometry often appears normal in early vaping-related lung injury; emerging evidence shows FeNO and advanced imaging (V/Q MRI) detect subclinical changes 6. However, these advanced tests are typically reserved for symptomatic patients or research settings.

Standard Age-Appropriate Preventive Screening

Cardiovascular Risk Assessment

Lipid panel (fasting or non-fasting):

• Total cholesterol, LDL-C, HDL-C, triglycerides
• Note: Smoking (including vaping) decreases HDL-C 7
• Vaping increases oxidative stress and endothelial dysfunction similar to traditional smoking 8, 9, 10

Blood pressure measurement: Vaping is associated with hypertension and arrhythmias 11

Fasting glucose or HbA1c: Standard diabetes screening for adults ≥45 years

High-sensitivity C-reactive protein (hs-CRP): Consider given inflammatory effects of vaping 9

• Dual users (cigarettes + e-cigarettes) show elevated inflammatory markers
• Exclusive e-cigarette users have lower but still measurable inflammatory biomarkers compared to never-users

Additional Laboratory Tests

Complete blood count (CBC):

• White blood cell count (WBC) positively correlates with smoking intensity 7
• Mean corpuscular volume (MCV) increases with smoking 7

Liver function tests: Standard screening

Renal function: Creatinine, eGFR

Urinalysis: Standard screening

Biomarkers of Tobacco Exposure (Optional)

If assessing smoking/vaping status objectively:

• Urinary cotinine: Best indicator of nicotine exposure (96-97% sensitivity, 99-100% specificity) 12
• Exhaled carbon monoxide: Acceptable discrimination (~90% sensitivity/specificity), cheaper and simpler than cotinine 12

Smoking and Vaping Cessation Intervention

This is the highest priority intervention for reducing morbidity and mortality 11.

The "5 A's" Approach 11

1. Ask: Document tobacco/vaping status at every visit as a vital sign
2. Advise: Firmly advise to quit both cigarettes and vaping with clear, compassionate language
3. Assess: Determine readiness to quit
4. Assist: Provide behavioral counseling + FDA-approved pharmacotherapy
5. Arrange: Schedule follow-up within 2 weeks of quit date

FDA-Approved Pharmacotherapy Options 11

• Nicotine replacement therapy: Patch, gum, lozenge, inhaler, nasal spray
• Varenicline (Chantix)
• Bupropion (Zyban)

Note: Black box warnings for neuropsychiatric events have been removed by the FDA 11

Critical Evidence on Vaping

While e-cigarettes show lower levels of some tobacco toxicant biomarkers compared to combustible cigarettes 8, they are not harmless:

• Vaping increases oxidative stress (F2-isoprostane levels) 9
• Cardiovascular risks include endothelial dysfunction, hypertension, and arrhythmias 10
• Pulmonary risks include EVALI, spontaneous pneumothorax, and chronic respiratory symptoms 13
• Dual users (cigarettes + e-cigarettes) have higher oxidative stress than cigarette-only smokers 9

Follow-Up Plan

At age 50: Reassess for lung cancer screening eligibility

• If ≥20 pack-year history: Initiate annual LDCT screening 2
• Screening should occur in organized programs with multidisciplinary expertise 1, 4

Ongoing: Annual cardiovascular risk assessment and continued cessation counseling at every visit

Common Pitfall: Do not assume vaping is "safer" and therefore acceptable. The evidence shows significant cardiovascular and pulmonary risks 10. Strongly advise complete cessation of all nicotine products.