There is provided a kit of parts for an exhaled breath condensate collection device. The kit comprises a mouthpiece module 100 comprising a breath passageway defined in the mouthpiece module 100 providing fluid conduction from a mouthpiece breath inlet port 122 for receiving exhaled breath to a mouthpiece breath outlet port 124 in use. The kit further comprises a collection vessel 300 for insertion into the device for cooling in use. The collection vessel 300 defines a sealed and resealable chamber for collecting exhaled breath condensate in use. The collection vessel has a vessel breath inlet 326 for admitting exhaled breath into the chamber. The kit of parts is configured such that the collection vessel 300 is: insertable into the device into an sample collection configuration in which the vessel breath inlet 326 is unsealed and in fluid communication with the mouthpiece breath outlet port 124 of the mouthpiece module 100 and removable from the device in a sample containment configuration in which the collection vessel chamber is resealed. One or more parts of the kit of parts is configured and/or operable such that the collection vessel 300 is caused to be resealed into the sample containment configuration after sample collection before the collection vessel 300 is fully removed from the device. The vessel inlet may be sealed with a film seal wherein the mouthpiece outlet port is moveable to penetrate the film on coupling of the mouthpiece breath outlet port in fluid communication with the vessel breath inlet. The resealing mechanism may be a sliding lid 322 which when in the sealed configuration covers and seals the vessel breath inlet.
