A container (e.g., bag, tube, collection card) intended to contain a specimen of air exhaled from a patient for subsequent in vitro determination of chemical and/or biological markers (e.g., volatile organic compounds) in the specimen to aid metabolic profiling or the diagnosis of disorders [e.g., lipid peroxidation levels, gastrointestinal H. pylori infection, coronavirus disease (COVID-19) infection]. It typically consists of carbon dioxide (CO2) absorbing material which may be encased within the container, a port/mouthpiece or an access device (e.g., tubing) to facilitate specimen collection, and/or an adaptor for connection to an analyser. This is a single-use device.