What are the initial lab tests and management recommendations for a newly diagnosed hypertensive patient?

Initial Laboratory Workup for Newly Diagnosed Hypertension

All newly diagnosed hypertensive patients require a standardized panel of routine laboratory tests to assess cardiovascular risk, detect target organ damage, and screen for secondary causes. 1

Mandatory Routine Laboratory Tests

The following tests should be obtained for every newly diagnosed hypertensive patient:

Renal Function Assessment

• Serum creatinine with calculated eGFR using the race-free CKD-EPI equation to detect chronic kidney disease and establish baseline renal function 1
• Urine albumin-to-creatinine ratio (ACR) to identify early kidney damage—this test is essential and should never be skipped, as it detects subclinical renal injury before creatinine rises 1
• Urinalysis with microscopy to assess for red blood cells, leukocytes, and casts that may indicate glomerular disease or other renal pathology 1

Metabolic and Electrolyte Panel

• Serum electrolytes (sodium and potassium) to detect hypokalemia (which may suggest primary aldosteronism) and establish baseline before initiating diuretics or RAS inhibitors 1
• Fasting blood glucose or HbA1c to screen for diabetes, as 7.5-8.4% of newly diagnosed hypertensives have undiagnosed diabetes 2
• Lipid panel (including LDL cholesterol) for cardiovascular risk stratification, as over 50% of hypertensive patients have dyslipidemia requiring treatment 2

Cardiac and Hematologic Assessment

• 12-lead electrocardiogram (ECG) to detect left ventricular hypertrophy, ischemic changes, or arrhythmias 1
• Complete blood count (CBC) with hemoglobin and platelet count to assess for anemia or thrombocytopenia 1
• Liver function tests including LDH and haptoglobin if clinically indicated 1

Cardiovascular Risk Stratification

After obtaining laboratory results, calculate 10-year cardiovascular disease risk:

• Use SCORE2 for patients aged 40-69 years or SCORE2-OP for patients ≥70 years 1
• Patients with ≥10% CVD risk, diabetes, moderate-to-severe CKD (eGFR <60 mL/min/1.73 m²), or established CVD are automatically high-risk and warrant immediate pharmacological treatment even with stage 1 hypertension (BP 140-159/90-99 mmHg) 1

Critical Timing for Follow-Up Labs

• Reassess electrolytes and renal function 2-4 weeks after initiating RAS inhibitors or diuretics to detect hyperkalemia or acute kidney injury 1
• Recent evidence demonstrates that complete baseline workup correlates with significantly better blood pressure control at 12 months (129.9 vs 142.8 mmHg systolic) compared to partial or no workup 2

Optional Tests Based on Clinical Indication

When to Order Additional Cardiac Testing

• Echocardiography if ECG shows abnormalities, cardiac murmurs are detected, or cardiac symptoms are present 1
• High-sensitivity cardiac troponin and NT-proBNP for assessing hypertension-mediated organ damage (HMOD) 1
• Coronary artery calcium (CAC) scoring by cardiac CT when results would change management decisions 1

When to Assess for Arterial Stiffness or Peripheral Disease

• Carotid-femoral or brachial-ankle pulse wave velocity (PWV) for arterial stiffness assessment in high-risk patients 1
• Ankle-brachial index if peripheral arterial disease is suspected based on symptoms or examination 1

When to Order Advanced Renal Imaging

• Renal ultrasound with Doppler in patients with CKD to assess kidney structure and exclude renovascular hypertension 1
• Fundoscopy if BP >180/110 mmHg to evaluate for hypertensive emergency or malignant hypertension (hemorrhages, exudates, papilledema) 1

Screening for Secondary Hypertension

Order additional testing when clinical features suggest secondary causes:

Red Flags Requiring Secondary Hypertension Workup

• Age <30 years at diagnosis or rapid onset/progression of hypertension 1
• Resistant hypertension (uncontrolled on 3+ medications including a diuretic) 1
• Hypokalemia (consider primary aldosteronism) 1
• Abdominal bruit on examination (renovascular hypertension) 1

Specific Tests for Secondary Causes

• Plasma or urinary fractionated metanephrines for suspected pheochromocytoma 1
• Plasma aldosterone and renin for primary aldosteronism screening 1
• Renal artery duplex Doppler or angiography for renovascular disease 1

Common Pitfalls to Avoid

• Do not skip urine ACR measurement—it is essential for detecting early kidney damage and required for all hypertensive patients, yet frequently omitted in practice 1
• Do not use race-based eGFR equations—always use the race-free CKD-EPI equation 1
• Do not order routine genetic testing—it is not recommended for typical hypertensive patients 1
• Do not delay treatment while awaiting specialty testing—initiate therapy based on routine labs and BP category, then pursue additional workup as indicated 1
• Do not assume normal baseline labs—comprehensive testing unmasks comorbidities (CKD, diabetes, dyslipidemia) in 35-54% of newly diagnosed hypertensives and correlates with better BP control 2