What initial investigations should I order for a 55-year-old patient with a blood pressure of 148/96 mmHg?

Initial Workup for a 55-Year-Old with Blood Pressure 148/96 mmHg

Order a basic metabolic panel (serum sodium, potassium, creatinine with eGFR), fasting lipid panel, fasting glucose or HbA1c, TSH, urinalysis with dipstick for protein, and a 12-lead ECG. 1, 2

Confirming the Diagnosis

Before initiating treatment, you must verify that this represents true sustained hypertension rather than an isolated elevated reading:

• Arrange home blood pressure monitoring or 24-hour ambulatory monitoring to confirm the diagnosis, as office readings may overestimate true blood pressure due to white-coat effect. 1, 2
• Home BP ≥135/85 mmHg or 24-hour ambulatory BP ≥130/80 mmHg confirms true hypertension requiring treatment. 1, 2
• Use a validated automated device with appropriate cuff size and obtain at least 2-3 readings per visit to ensure accuracy. 2

Essential Laboratory Investigations

The basic workup serves three purposes: identifying cardiovascular risk factors, screening for secondary causes, and detecting target-organ damage. 1

Metabolic and Renal Assessment

• Serum electrolytes (sodium, potassium) – hypokalemia may suggest primary aldosteronism; baseline potassium is essential before starting diuretics or ACE inhibitors/ARBs. 1
• Serum creatinine with eGFR – identifies chronic kidney disease, which influences drug selection and blood pressure targets. 1
• Urinalysis with dipstick for protein – proteinuria indicates renal parenchymal disease or hypertensive nephropathy. 1

Cardiovascular Risk Stratification

• Fasting lipid panel – essential for calculating 10-year atherosclerotic cardiovascular disease (ASCVD) risk, which determines treatment intensity. 1, 3
• Fasting glucose or HbA1c – diabetes is a major cardiovascular risk factor and influences blood pressure targets (<130/80 mmHg). 1, 2, 3
• 12-lead ECG – screens for left ventricular hypertrophy, prior myocardial infarction, or arrhythmias that indicate target-organ damage. 1

Thyroid Function

• TSH – both hyperthyroidism and hypothyroidism can cause or worsen hypertension; this is part of the basic secondary hypertension screen. 1

Clinical History and Physical Examination

While obtaining laboratory tests, gather specific information that guides management:

History Elements to Document

• Duration and previous levels of blood pressure – sudden onset or rapid progression suggests secondary causes. 1
• Medications and substances that raise blood pressure: NSAIDs, decongestants, oral contraceptives, systemic corticosteroids, licorice, cocaine, amphetamines. 1
• Family history of hypertension, premature coronary disease, stroke, diabetes, or kidney disease. 1
• Lifestyle factors: dietary sodium intake, alcohol consumption (quantify drinks per week), physical activity level, smoking status, weight gain since early adulthood. 1, 2
• Symptoms suggesting secondary hypertension: snoring/daytime sleepiness (sleep apnea), muscle weakness/cramps (primary aldosteronism), palpitations/headaches/sweating (pheochromocytoma), flank pain (polycystic kidney disease). 1

Physical Examination Findings

• Measure heart rate over at least 30 seconds – persistent tachycardia (>90 bpm) indicates increased cardiovascular risk. 1
• Waist circumference, height, and weight to calculate BMI – obesity is a major modifiable risk factor. 1, 2
• Fundoscopic examination for retinal changes (arteriovenous nicking, hemorrhages, exudates, papilledema). 1
• Cardiac examination: displaced apical impulse (left ventricular hypertrophy), S4 gallop, murmurs. 1
• Abdominal examination: palpate for enlarged kidneys (polycystic kidney disease), auscultate for renal artery bruits (renovascular hypertension). 1
• Peripheral pulses: check all four extremities; diminished/delayed femoral pulses suggest aortic coarctation. 1

When to Screen for Secondary Hypertension

At this initial presentation with BP 148/96 mmHg in a 55-year-old, extensive secondary hypertension workup is not routinely indicated unless specific red flags are present. 1

Consider further investigation for secondary causes if:

• Age <30 years with hypertension (especially without obesity, metabolic syndrome, or family history). 1
• Sudden onset or rapid worsening of previously controlled blood pressure. 1
• Resistant hypertension (BP ≥140/90 mmHg despite three drugs including a diuretic at optimal doses). 1
• Severe hypertension (BP ≥180/110 mmHg). 1
• Strong clinical clues from history or physical examination (e.g., hypokalemia, abdominal bruit, features of Cushing syndrome). 1

Blood Pressure Targets

• Primary target: <130/80 mmHg for most adults, especially those with diabetes, chronic kidney disease, or established cardiovascular disease. 2, 3, 4
• Minimum acceptable target: <140/90 mmHg for lower-risk individuals. 2, 3, 4

Next Steps After Initial Workup

Once you have confirmed sustained hypertension and completed the basic workup:

• Initiate lifestyle modifications immediately: sodium restriction to <1500-2000 mg/day, DASH or Mediterranean diet, weight loss if BMI ≥25 kg/m², regular aerobic exercise (≥150 minutes/week), alcohol limitation (≤2 drinks/day for men, ≤1 for women), smoking cessation. 2, 3
• Start pharmacologic therapy with combination treatment (RAS blocker + calcium channel blocker or RAS blocker + thiazide-like diuretic), preferably as a single-pill combination to improve adherence. 2, 3, 4
• Schedule follow-up in 2-4 weeks to assess blood pressure response, review home monitoring results, check for medication side effects, and reinforce lifestyle changes. 2

Common Pitfalls to Avoid

• Do not start treatment based on a single office reading – confirm with home or ambulatory monitoring to avoid treating white-coat hypertension. 1, 2
• Do not order extensive secondary hypertension workup (renal imaging, aldosterone/renin ratio, sleep study) in a 55-year-old with stage 1 hypertension and no red flags – this wastes resources and delays treatment. 1
• Do not delay lifestyle counseling until after laboratory results return – dietary sodium reduction and weight loss can begin immediately and provide 10-20 mmHg systolic reduction. 2, 3
• Do not forget to calculate 10-year ASCVD risk once you have the lipid panel and glucose results, as this determines treatment intensity and statin candidacy. 3