From the Guidelines
When suspecting pulmonary hypertension, initial laboratory tests should include a complete blood count, comprehensive metabolic panel, thyroid function tests, brain natriuretic peptide (BNP) or N-terminal pro-BNP levels, autoimmune serologies, HIV testing, coagulation studies, and arterial blood gases to aid in diagnosis and identify underlying causes. These tests are essential in evaluating the patient's condition and guiding further management.
Key Laboratory Tests
- Complete blood count to assess for polycythemia, anemia, and thrombocytopenia 1
- Comprehensive metabolic panel to evaluate liver and kidney function 1
- Thyroid function tests to assess for hypothyroidism or hyperthyroidism 1
- Brain natriuretic peptide (BNP) or N-terminal pro-BNP levels to evaluate right ventricular strain and disease severity 1
- Autoimmune serologies, including ANA, anti-centromere antibody, and anti-Scl-70, to identify connective tissue diseases associated with pulmonary hypertension 1
- HIV testing, as HIV infection is a known risk factor 1
- Coagulation studies to reveal hypercoagulable states contributing to chronic thromboembolic pulmonary hypertension 1
- Arterial blood gases to assess oxygenation status and acid-base balance 1
Imaging Studies and Right Heart Catheterization
Imaging studies, such as echocardiography, and right heart catheterization, which remains the gold standard for definitive diagnosis of pulmonary hypertension, complement these laboratory tests 1. The most recent guidelines recommend radiography chest, US echocardiography transthoracic resting, CT chest with IV contrast, or CTA chest with IV contrast for the initial imaging of patients with suspected pulmonary hypertension 1.
From the Research
Diagnostic Tests for Pulmonary Hypertension
When suspecting pulmonary hypertension, several labs and tests can be considered to aid in diagnosis and classification. These include:
- Electrocardiography to assess cardiac function 2
- Chest radiography to evaluate lung structure and detect any abnormalities 2, 3
- Pulmonary function tests to assess lung function and detect any underlying lung diseases 2, 3
- Transthoracic echocardiography to estimate pulmonary artery pressure and assess right ventricular function 2, 3
- Ventilation-perfusion scan to exclude chronic thromboembolic pulmonary hypertension (CTEPH) 2
- Right-sided heart catheterization to accurately diagnose and classify pulmonary hypertension 2, 4
- Blood tests, such as brain natriuretic peptide (BNP), to assess disease severity and prognosis 3
- Arterial blood gas analysis to assess oxygenation and ventilation 3
- High-resolution computed tomography of the lungs to evaluate lung structure and detect any abnormalities 3
- Contrast-enhanced spiral computed tomography of the lungs to evaluate pulmonary vasculature 3
- Pulmonary angiography to evaluate pulmonary vasculature and detect any thromboembolic disease 3
Classification and Diagnosis
Pulmonary hypertension can be classified into five clinical groups based on etiology, pathophysiology, and treatment 2, 4. Accurate diagnosis and classification are essential to guide treatment and management. The diagnostic algorithm typically involves a combination of non-invasive and invasive tests to assess pulmonary artery pressure, right ventricular function, and underlying lung disease.
Specialized Tests
In certain cases, specialized tests may be necessary to aid in diagnosis and classification. These include:
- Exercise capacity assessment to evaluate functional capacity and disease severity 3
- Hemodynamic evaluation to assess pulmonary vascular resistance and right ventricular function 3
- Immunology tests to detect autoantibodies and assess autoimmune phenomena 5, 6
- Abdominal ultrasound scan to evaluate liver function and detect any underlying liver disease 3