What simplified laboratory tests are recommended for a patient with hypertension to assess kidney function and cardiovascular risk factors?

Simplified Laboratory Testing for Hypertensive Patients

For a patient with hypertension, the essential simplified laboratory workup includes serum sodium, potassium, creatinine with estimated glomerular filtration rate (eGFR), dipstick urinalysis, and when available, fasting glucose and lipid profile. 1

Core Laboratory Tests (Essential)

The 2020 International Society of Hypertension guidelines establish a streamlined approach that can be implemented in any clinical setting:

Blood Tests - Mandatory

• Sodium and potassium: Essential for detecting electrolyte abnormalities that may indicate secondary causes (particularly primary aldosteronism with hypokalemia) 1, 2, 3
• Serum creatinine and eGFR: Critical for assessing kidney function and identifying chronic kidney disease (eGFR <60 ml/min/1.73m² indicates moderate-severe CKD and hypertension-mediated organ damage) 1, 2

Blood Tests - When Available

• Fasting glucose: Identifies diabetes, present in 15-20% of hypertensive patients and a major cardiovascular risk modifier 1, 2, 4
• Lipid profile (LDL-cholesterol and triglycerides): Dyslipidemia affects 30% of hypertensive patients and substantially increases cardiovascular risk 1, 2, 4

Urine Test

• Dipstick urinalysis: Simple screening for proteinuria and hematuria indicating kidney damage 1

Additional Testing Based on Initial Results

When Basic Tests Suggest Organ Damage or Secondary Causes

• Urinary albumin/creatinine ratio: Perform if dipstick shows proteinuria or if diabetes/CKD is present 1
• Serum uric acid: Common in hypertension (25% prevalence) and may guide treatment selection 1, 4

When Screening for Secondary Hypertension

The European Society of Cardiology 2024 guidelines now recommend measuring aldosterone-to-renin ratio in all adults with confirmed hypertension, representing a major shift from selective screening 3. However, this is particularly critical when:

• Unprovoked hypokalemia is present 3
• Resistant hypertension (requiring >3 medications) 3
• Age of onset <30 or >50 years 3

Electrocardiogram

12-lead ECG is part of the simplified workup to detect: 1

• Atrial fibrillation
• Left ventricular hypertrophy (indicates hypertension-mediated organ damage)
• Ischemic heart disease

Clinical Reasoning for This Approach

This simplified panel efficiently accomplishes multiple goals simultaneously:

Kidney function assessment (creatinine/eGFR, urinalysis): Identifies both hypertension-mediated organ damage and potential secondary causes, while guiding medication selection 1, 2

Cardiovascular risk stratification: The combination of glucose and lipids identifies the metabolic syndrome components that affect 40% of hypertensive patients and dramatically increase morbidity and mortality 1, 4

Secondary hypertension screening: Electrolytes detect primary aldosteronism (the most common secondary cause), while creatinine abnormalities may suggest renovascular disease 1, 3

Common Pitfalls to Avoid

Do not order extensive imaging or specialized hormonal testing initially unless clinical clues warrant it (resistant hypertension, suggestive symptoms, age extremes) 3, 5. The simplified approach detects target organ damage and excludes secondary causes adequately in most patients 6, 7.

Medication review is essential before extensive workup: NSAIDs, oral contraceptives, decongestants, glucocorticoids, and substances like cocaine can cause hypertension and are more common causes of resistant hypertension than rare secondary causes 3, 7.

Biochemical monitoring after treatment initiation is often omitted: Only 36.4% of newly treated hypertensive patients receive appropriate follow-up laboratory testing within 6 months, yet this monitoring detects adverse drug reactions that would otherwise go unrecognized 8.

Resource-Limited Settings

In settings where lipid profile and glucose testing are unavailable, the absolute minimum workup remains: 1

• Sodium and potassium
• Serum creatinine with eGFR
• Dipstick urinalysis
• 12-lead ECG

This minimal panel still identifies kidney dysfunction, electrolyte disorders suggesting secondary causes, and cardiac end-organ damage—the factors most directly impacting mortality and morbidity.