The present invention includes an apparatus and a method for testing exhaled breath condensate for at least one biometric marker, including a substrate for collecting exhaled breath condensate, the substrate capable of being brought to a temperature below a dew point of vapor in exhaled breath, a collector for retaining the substrate and for receiving a biometric marker reagent. The invention may further include receiving exhaled breath in a collector, the collector comprising a substrate, the substrate being at a temperature below a dew point of vapor in exhaled breath, collecting the exhaled breath condensate on the substrate, and bringing a biometric marker reagent in contact with the substrate.