Abstract: An apparatus for use in an assay to be conducted upon a fluid sample suspected of containing an analyte of interest, comprises a vessel for receiving a sample, and an element for capturing an analyte of interest. The element is insertable into the vessel for the purposes of the assay, and is coated on at least one surface with a specific binding partner for the analyte of interest. The element further having on a surface remote from the coated surface, structure adapted for manipulating the element for convenient analysis, whereby it is possible to detect and quantify microorganisms, particularly assay for infective agents such as bacteria, and viral particles and prions, or other particles that may be associated with a disease state, especially in humans.