Sample collection assemblies and methods that use a collection wand having a working end and an operating end, a collection tube having a barrel portion, an assay chamber, and a partition member, with the working end of the collection wand having a scoop configured for collecting a predetermined sample volume, and with the partition member having an orifice with a boundary complementary to a cross-section of the scoop, whereby an excess of sample material can be excluded from entering the assay chamber.