Pulmonary function test (PFT)
Except for PH related to hypoxic lung disorders (DanaPoint world coference group 3), a regular follow-up of lung function is not necessary in PAH/PH. Carbon monoxide diffusion capacity (DLCO) is not a predictive parameter for prognosis nor does it correlate to improvement under therapy.
However SaO₂ measured with a pulse oxymeter is standard practice. When the value is under 90% at room air, blood gases analysis should be performed. Although the exact criteria for long term oxygen therapy are not established for PAH/PH, a night oxymetry may be useful in order to evaluate the need for home supplemental oxygen. In Switzerland this treatment is prescribed by a board-certified pneumologist.