Initial Laboratory Workup for Severe Hypertension

Essential Laboratory Tests

• The European Society of Cardiology recommends that patients with severe hypertension should undergo complete blood count, urinalysis, serum electrolytes, blood urea nitrogen, serum creatinine, fasting blood glucose, lipid profile, liver function tests, and thyroid-stimulating hormone as part of their initial laboratory workup 1, 2
• The American College of Cardiology suggests that blood tests should include complete blood count 3, 2, serum electrolytes (sodium, potassium, calcium, magnesium) 3, 1, blood urea nitrogen and serum creatinine with estimated glomerular filtration rate (eGFR) 3, 1, 2, fasting blood glucose and/or glycated hemoglobin (HbA1c) 1, 2, lipid profile (total cholesterol, LDL, HDL, triglycerides) 3, 1, liver function tests 3, 1, and thyroid-stimulating hormone (TSH) [3, 1, 2] [3, 1, 2]
• Urine tests should include urinalysis 3, 1 and urinary albumin-to-creatinine ratio 1, 2
• A 12-lead electrocardiogram is recommended as part of the cardiac assessment 3, 1, 2

Rationale for Testing

• The European Heart Journal states that these laboratory tests help identify target organ damage, such as kidney function tests (creatinine, eGFR, urinary albumin) 1, 5
• The American College of Cardiology recommends screening for secondary causes of hypertension using electrolytes, TSH, and kidney function tests 3, 2
• The European Heart Journal suggests that lipid profile and glucose measurements help assess cardiovascular risk 1, 4
• Baseline values of electrolytes and kidney function are essential before initiating medications like diuretics or RAS blockers, according to the Journal of the American College of Cardiology 2, 6

Additional Tests to Consider Based on Clinical Presentation

• Echocardiography is recommended when ECG is abnormal, cardiac murmurs are detected, or cardiac symptoms are present, as stated by the European Heart Journal 5, 1
• Fundoscopy is essential in severe hypertension to assess for hypertensive retinopathy, hemorrhages, or papilledema, according to Hypertension 3, 7
• Additional imaging, such as renal ultrasound, should be considered if kidney disease is suspected or in resistant hypertension, as recommended by the European Heart Journal 5, 1

Clinical Implications of Laboratory Findings

• Abnormal electrolytes, such as hypokalemia, may suggest primary aldosteronism, while hyperkalemia may indicate kidney dysfunction or medication effects, as stated by Hypertension 3, 4
• Elevated creatinine or reduced eGFR indicates kidney damage and influences treatment decisions, according to the European Heart Journal 1, 7
• Elevated glucose or HbA1c identifies comorbid diabetes, which significantly increases cardiovascular risk, as stated by the European Heart Journal 1
• Abnormal lipids guide decisions about statin therapy in addition to BP management, according to the European Heart Journal 1
• Proteinuria or albuminuria indicates kidney damage and is an independent cardiovascular risk factor, as stated by the European Heart Journal 5, 1

Common Pitfalls to Avoid

• Ignoring baseline values before starting medications can make it difficult to monitor for medication side effects, as warned by the Journal of the American College of Cardiology 2