Abstract: Methods and apparatus are already in use in the field of veterinary medicine for detecting microfilariae of heartworm in blood, comprising lysing blood samples to destroy corpuscular components, filtering the lysed samples on microporous transparent filters, staining any microfilariae on the filter, and observing the stained microfilariae under a microscope. The present invention simplifies and improves upon the older practices by providing a premix of lysing solution and staining dye, in a disposable vial, and a disposable filtrate vial surmounted by disposable filter cap holding a microporous filter element. The blood sample is injected into the premix for simultaneous lysing and staining, transferred to the filter cap for filtration and the filter element transferred to a microscope slide for observation.

Abstract: A filter thimble adapted for use in a float-or-sink process of separating ova from samples of feces contained in standarized transport receptacles has an outside diameter of about 3/4 that of the inside of the receptacle, has a bottom, has an open top, has around its upper side surface a closure operatively fittable to the transport receptacle, and around its lower side surface numerous perforations of dimension only several times larger than the ova. The under surface of the closure is frusto-conical, with smaller end up and fitted liquid-tight to the outside of the thimble, and several of the perforations have their outer openings immediately below the point of fit.