What labs are included in a comprehensive hypertensive workup for a patient with a history of hypertension and gastroesophageal reflux disease (GERD)?

Hypertensive Workup: Laboratory Tests

The essential laboratory workup for hypertension includes serum sodium, potassium, creatinine with eGFR, fasting glucose, lipid profile, urinalysis with dipstick, and a 12-lead ECG. 1

Core Laboratory Tests (Required for All Patients)

Blood Tests

• Serum electrolytes: Sodium and potassium to screen for primary aldosteronism (hypokalemia suggests this diagnosis) and assess baseline status 1, 2
• Renal function: Serum creatinine and estimated glomerular filtration rate (eGFR) to detect chronic kidney disease, which affects 35.5% of hypertensive patients with creatinine >0.8 mg/dL and 7.5% with eGFR <60 mL/min/1.73m² 1, 2, 3
• Metabolic assessment: Fasting glucose (abnormal in 8.4% of newly diagnosed patients) and lipid profile including LDL-cholesterol (elevated in 54.2% of patients) 1, 2, 3

Urine Tests

• Dipstick urinalysis: Screens for hematuria, proteinuria, and kidney damage 1, 2
• Urinary albumin-to-creatinine ratio (UACR): Detects early kidney damage and serves as an independent cardiovascular risk factor 1, 2, 4

Electrocardiogram

• 12-lead ECG: Mandatory in all patients to detect atrial fibrillation, left ventricular hypertrophy, and ischemic heart disease 1, 2, 4

Additional Laboratory Tests When Clinically Indicated

Expanded Metabolic Panel

• HbA1c: Consider if fasting glucose is borderline or diabetes is suspected (abnormal in 7.5% of newly diagnosed hypertensive patients) 2, 3
• Serum uric acid: Check if levels may guide treatment decisions, as hyperuricemia affects 25% of hypertensive patients; treatment recommended if >6 mg/dL with gout symptoms 1, 2
• Liver function tests: Include in comprehensive assessment 1, 2

Secondary Hypertension Screening (When Suspected)

Order these tests only when clinical features suggest specific secondary causes: 1, 2, 5

• Aldosterone-to-renin ratio: For suspected primary aldosteronism (8-20% of resistant hypertension cases), especially with hypokalemia, muscle weakness, or resistant hypertension 1, 2, 5
• Plasma free metanephrines: For suspected pheochromocytoma with episodic symptoms, sweating, palpitations, or labile hypertension 1, 2, 5
• Late-night salivary cortisol or 24-hour urinary free cortisol: For suspected Cushing syndrome with cushingoid features, fatty deposits, or colored striae 1, 2, 5

Clinical Context: GERD Does Not Alter Standard Workup

The presence of gastroesophageal reflux disease does not modify the standard hypertensive laboratory evaluation. However, be aware that calcium channel blockers (commonly used antihypertensives) can worsen GERD symptoms by decreasing lower esophageal sphincter tone. 6

Evidence Supporting Complete Workup

A complete baseline workup significantly improves blood pressure control. Recent evidence demonstrates that patients receiving complete laboratory testing achieved better systolic blood pressure control at 12 months (129.9 mmHg) compared to those with partial workup (142.8 mmHg, p=0.003). 3 This complete workup also unmasks critical comorbidities including chronic kidney disease, diabetes, and dyslipidemia that require concurrent management. 3

Common Pitfalls to Avoid

• Don't skip the urinalysis: Proteinuria or albuminuria indicates kidney damage and significantly increases cardiovascular risk, yet is often overlooked 2, 4
• Don't order expensive imaging before basic labs: Complete the basic laboratory screening before proceeding to specialized tests or imaging studies 5
• Don't forget to check potassium before starting therapy: Baseline potassium is essential as many antihypertensive medications affect potassium levels, and hypokalemia may indicate primary aldosteronism 1, 2
• Don't order secondary hypertension screening in everyone: Reserve aldosterone-renin ratio, metanephrines, and cortisol testing for patients with specific clinical clues (age <30 years, resistant hypertension, hypokalemia, episodic symptoms, cushingoid features) 1, 2, 5

Risk Stratification Context

More than 50% of hypertensive patients have additional cardiovascular risk factors that proportionally increase their risk of coronary, cerebrovascular, and renal disease. 1, 2 The laboratory workup identifies these modifiable risk factors (diabetes in 15-20%, dyslipidemia in 30%, hyperuricemia in 25%) to guide comprehensive cardiovascular risk reduction. 1, 2