What baseline laboratory workup should be performed for a 50‑year‑old man with erectile dysfunction and a normal physical exam before starting therapy, including fasting glucose/HbA1c, lipid panel, morning total testosterone, and basic metabolic panel?

Baseline Laboratory Workup for Erectile Dysfunction

Yes, comprehensive metabolic and cardiovascular screening is mandatory before starting ED therapy—specifically morning total testosterone, fasting glucose or HbA1c, and fasting lipid panel—because ED is a powerful independent marker for cardiovascular disease and these tests directly influence treatment selection and identify life-threatening comorbidities. 1, 2, 3

Required Baseline Laboratory Tests

Morning Total Testosterone (Mandatory)

• Measure morning serum total testosterone (drawn between 8-10 AM) in every man presenting with ED, regardless of age or symptoms 1, 2, 4, 3
• Testosterone <300 ng/dL defines deficiency and requires specific hormonal therapy before or alongside ED treatment 2, 4
• Low testosterone explains poor response to PDE5 inhibitors and must be corrected for optimal ED treatment outcomes 2, 4
• If initial level is low, repeat testing is recommended to confirm the diagnosis 1
• Testosterone therapy improves both erectile function and libido in hypogonadal men, and enhances response to PDE5 inhibitors 1, 2

Fasting Glucose or HbA1c (Mandatory)

• Fasting glucose or HbA1c must be checked because diabetes severity directly correlates with ED risk and poor glycemic control predicts treatment failure 2, 4, 3
• HbA1c ≥6.5% (47.5 mmol/mol) is associated with 3.7-fold increased odds of ED 5
• Fasting plasma glucose ≥126 mg/dL (>7 mmol/L) carries 2.68-fold increased odds of ED 5
• Even prediabetic ranges (HbA1c 5.7-6.4% or FPG 100-126 mg/dL) significantly increase ED risk 5
• Diabetes management directly impacts ED outcomes and must be optimized concurrently 2, 3

Fasting Lipid Panel (Mandatory)

• Fasting lipid profile (total cholesterol, LDL, HDL, triglycerides) should be considered mandatory in all newly presenting ED patients 2, 3
• Dyslipidemia is a modifiable cardiovascular risk factor that must be assessed before testosterone therapy 1
• The triglyceride-glucose (TyG) index, calculated from fasting glucose and triglycerides, independently predicts ED (cutoff value 8.88 with 67% sensitivity and 68.6% specificity) 6
• Elevated cholesterol was found in 15% of ED patients in screening studies 7
• Lipid abnormalities require management to prevent long-term cardiovascular morbidity and mortality, even if they don't immediately resolve ED 7

Hemoglobin/Hematocrit (Required if Considering Testosterone)

• Measure baseline hemoglobin/hematocrit before initiating testosterone therapy 1
• Withhold testosterone if hematocrit exceeds 50% until etiology is investigated 1
• On-treatment hematocrit >54% warrants dose reduction or temporary discontinuation 1

PSA (Required for Men Over 40 if Considering Testosterone)

• PSA should be measured in men over 40 years before commencing testosterone therapy to exclude occult prostate cancer 1
• If PSA is elevated at baseline, obtain a second measurement to rule out spurious elevation 1
• Two elevated PSA levels warrant formal evaluation, potentially including reflex testing and prostate biopsy, before starting testosterone 1

Additional Cardiovascular Risk Assessment

Why This Matters for Morbidity and Mortality

• ED is a substantial independent risk marker for cardiovascular disease that can precede coronary symptoms by 2-5 years, with prognostic weight comparable to smoking or family history of myocardial infarction 2, 4
• All testosterone-deficient patients must be assessed for ASCVD risk factors (dyslipidemia, hypertension, diabetes, smoking) before offering testosterone therapy 1
• Men with organic ED should be considered at increased cardiovascular disease risk until proven otherwise, even without cardiac symptoms 2

Blood Pressure and Vital Signs

• Measure blood pressure and pulse at baseline 1, 4
• Document resting blood pressure as part of cardiovascular risk stratification 1

Tests That Are NOT Immediately Necessary for ED Management

Basic Metabolic Panel

• Not specifically recommended in ED guidelines unless clinically indicated for other reasons
• Renal function becomes relevant only if considering metformin or if other comorbidities warrant assessment 1

Liver Function Tests

• Abnormal findings occur in 12.8% of ED patients but do not change standard ED therapy 7
• Required before testosterone therapy as part of ongoing monitoring 1

Clinical Algorithm

Step 1: Obtain morning total testosterone (8-10 AM), fasting glucose or HbA1c, and fasting lipid panel in every 50-year-old man presenting with ED 1, 2, 4, 3

Step 2: If testosterone <300 ng/dL, repeat measurement and initiate testosterone replacement therapy, as this improves ED outcomes and PDE5 inhibitor response 1, 2, 4

Step 3: If HbA1c ≥5.7% or fasting glucose ≥100 mg/dL, optimize glycemic control as diabetes severity directly predicts ED treatment failure 5, 3

Step 4: If lipids are abnormal, initiate cardiovascular risk reduction because ED signals underlying vascular disease requiring aggressive management 2, 3

Step 5: Before starting testosterone (if indicated), add PSA and hemoglobin/hematocrit to exclude contraindications 1

Common Pitfalls to Avoid

• Failing to check testosterone leads to missed hypogonadism, which explains poor PDE5 inhibitor response and requires separate treatment 2, 4
• Missing cardiovascular disease screening, as ED may be the first presentation of significant vascular disease requiring urgent intervention 2, 4, 3
• Not obtaining fasting glucose/HbA1c and lipids, which identify modifiable risk factors that directly impact both ED outcomes and long-term survival 7, 5, 3
• Treating ED in isolation without addressing the underlying cardiovascular and metabolic derangements that drive both the sexual dysfunction and future cardiac events 2, 3