Abstract: Methods of capturing and labeling a species, include attracting magnetically attractable particles to a solid support by magnetic forces, which particles have an affinity for the species, contacting the particles on the support with a sample containing the species to capture the species onto the particles on the support, and binding the species captured on the particles directly or indirectly to a detectable label before and/or whilst the species is captured on the particles on the support. The label may be bound to the captured species via an immunological binding partner which binds selectively to the species and may be a fluorescent label, luminescent label, enzyme label, dye label, phosphorescent label, metal-chelating label, radio label, spin label, heavy metal label, nucleic acid or nucleic acid analog hybridization label, avid or avid-like label suitably bound to or incorporated in particles which also bear a binding agent such as an antibody causing the particles to bind to the captured species.

Abstract: A species such as a microorganism, e.g. Legionella, Giardia or Cryptosporidium, is captured by first attracting plastic coated magneticbeads or other magnetically attractable particles to a solid support such as stainless steel mesh, which particles have a selective affinity for the species, e.g. by virtue of an antibody coating, and contacting a sample containing the species with the particles on the solid support. The beads bearing the captured species may be released by reduction of the magnetic attraction of the support for the beads, e.g. by turning off an electromagnet used to magnetize the support.

Abstract: An expansible, compressed foam is used a s a filter medium and captured particulates are released from the foam by expanding the foam to open its pores. Micro-organisms such as Cryptosporidium or Giardia cysts may be trapped and recovered at high eficiency in a small volume of wash liquid easing further analysis. A foam filter element comprises thirty discs (36) of retriculated foam compressed between end plates (28,30) to about one tenth of their original thickness.