The present invention provides adiagnostic kit for detecting the presence or quantity of one or more test analytes within a test sampletaken from a body surface of a mammal the diagnostic kit comprising:a separate insert for a lateral flow device (200 411) comprising a membrane (201) fixed to a rigid support (202) and the separate insert being configured to obtain the test sample a lateralflow assay device configured (300 400) to accept the separate insert (200 411) a securing member (210) configured to releasably attach (211) the separate insert to a body surface of a mammal (213) wherein the securing member (210) comprise an expandable layer (212) configured to apply pressure to the separate insert (200 411) thereby pressing the separate insert (200 411) against the body surface of the mammal (213).
