A non-transitory processor readable medium storing code representing instructions to be executed by a processor, the code configured to cause the processor to:
- determine, based on a first signal received from a gas analyzer, a first measured concentration of a test gas contained within a first gas mixture injected into a pulmonary function test device from a syringe having a first mixing ratio;
- determining, based on a second signal received from the gas analyzer, a second measured concentration of the test gas contained within a second gas mixture injected into the pulmonary function test device from the syringe, the second gas mixture including a portion of the first gas mixture diluted with atmospheric gas according to the first mixing ratio;
- determining, based on a third signal received from the gas analyzer, a third measured concentration of the test gas contained within a third gas mixture injected into the pulmonary function test device from the syringe, the third gas mixture including a portion of the second gas mixture diluted with atmospheric gas according to the first mixing ratio;
- determine a measured decay rate based on the first measured concentration of the test gas, the second measured concentration of the test gas, and the third measured concentration of the test gas;
- define, for the gas analyzer, an eigenfunction over the measured decay rate;
- determine, based on a fourth signal received from the gas analyzer, a fourth measured concentration of the test gas contained within a fourth gas mixture injected into the pulmonary function test device from the syringe;
- determine, based on a fifth signal received from the gas analyzer, a fifth measured concentration of the test gas contained within a fifth gas mixture injected into the pulmonary function test device from the syringe, the fifth gas mixture including a portion of the fourth gas mixture concentrated with the test gas according to a second mixing ratio;
- determine, based on a sixth signal received from the gas analyzer, a sixth measured concentration of the test gas contained within a sixth gas mixture injected into the pulmonary function test device from the syringe, the sixth gas mixture including a portion of the fifth gas mixture concentrated with the test gas according to the second mixing ratio;
- determine a measured concentration rate based on the fourth measured concentration of the test gas, the fifth measured concentration of the test gas, and the sixth measured concentration of the test gas;
- define, for the gas analyzer, an eigenfunction over the measured concentration rate;
- simultaneously determine, by simultaneously solving the eigenfunction over the measured decay rate and the eigenfunction over the measured concentration rate, the first mixing ratio, the second mixing ratio, and a set of coefficients representing a non-linearity of the gas analyzer.