Patent ID: 8485983

Claim:
A method for diagnosing a medical condition in a subject, said method comprising the steps of: a) providing an apparatus for selectively detecting a presence of a gaseous compound in a mixture of gases, wherein said apparatus comprises a probe, said probe comprising: i) a first sensor responsive to the presence of a gaseous oxidizing compound, a second sensor responsive to a gaseous reducing compound containing no nitrogen, and a third sensor responsive to a gaseous reducing compound containing nitrogen, each said sensor comprising an undoped crystalline form of a transition metal oxide disposed within said sensor in a thin film of said crystals to create in said thin film an electrical property that is selectively responsive to said gaseous compound, wherein said crystals in said first sensor comprise rhenium oxide structured crystals, said crystals in said second sensor comprise rutile structured crystals, and said crystals in said third sensor comprise αMoO 3 -structured crystals, and ii) an analyzer, wherein said analyzer is electrically connected to each of said sensors such that said analyzer measures changes in said electrical property of each said sensor; b) exposing the probe to a breath of the subject, and c) using the analyzer to determine the presence in the breath of the subject of one or more of said gaseous compounds, wherein said presence is indicative of said medical condition of the subject.