Abstract: A test apparatus for evaluating a measuring device for measuring a diffusion capacity of a person's lungs by measuring a change of concentration of a gas species in a mixture, when the mixture is inhaled and subsequently exhaled by a person, wherein the test apparatus includes (a) a port for connecting to the measuring device; (b) a compartment coupled to the port; (c) a circulation circuit configured to circulate gas from the compartment back to the compartment; and (d) a gas species removing element configured to selectively reduce a partial pressure of the gas species at a point in the circulation circuit.

Abstract: A test apparatus for evaluating a measuring device for measuring a diffusion capacity of a person's lungs by measuring a change of concentration of a gas species in a mixture, when the mixture is inhaled and subsequently exhaled by a person, wherein the test apparatus includes (a) a port for connecting to the measuring device; (b) a compartment coupled to the port; (c) a circulation circuit configured to circulate gas from the compartment back to the compartment; and (d) a gas species removing element configured to selectively reduce a partial pressure of the gas species at a point in the circulation circuit.

Abstract: A method of evaluating a measuring device for measuring, in normal operation, a diffusion capacity of a person's lungs by measuring a change of concentration of a gas species in a mixture, when the mixture is inhaled and subsequently exhaled by the person or imposed by an artificial ventilator, the method comprising the steps of: (a) receiving the mixture in a compartment; (b) circulating gas from the compartment back to the compartment through a circulation circuit; and (c) selectively reducing partial pressure of the gas species in the circulation circuit to a predetermined level. A device for implementing the evaluation method is also disclosed.

Abstract: A method of evaluating a measuring device for measuring, in normal operation, a diffusion capacity of a person's lungs by measuring a change of concentration of a gas species in a mixture, when the mixture is inhaled and subsequently exhaled by the person or imposed by an artificial ventilator, the method comprising the steps of: (a) receiving the mixture in a compartment; (b) circulating gas from the compartment back to the compartment through a circulation circuit; and (c) selectively reducing partial pressure of the gas species in the circulation circuit to a predetermined level. A device for implementing the evaluation method is also disclosed.