A system for collecting and retaining a sample from exhaled breath of a subject for analysis can include a two part housing, a two part trap section, and optionally a boat fitment. Disclosed is a portable fluid sampling device comprising: a housing including a first portion removably attachable to a second portion, the first and second portions being configured to combine to form a chamber therein, the chamber being configured to at least temporarily contain or hold a biological sample therein, at least one of the first portion and the second portion including an inlet, the other of the first portion and the second portion including an outlet, wherein the device further comprises at least one of the following: a) one of the first portion and the second portion including an end having a projection, the other of the first portion and the second portion including an end having a groove, the groove being configured to receive at least a portion of the projection therein； or b) tamper evident means for indicating that the first portion of the housing has previously been separated from the second portion of the housing.
