Abstract: The integral reagent dispenser disclosed comprises a reagent dispenser component provided with a reagent dispenser well having an opening adapted to present a liquid reagent for withdrawal therethrough and means to position a lens of liquid immiscible with said reagent between the reagent and the opening of said well. For example, the dispenser can have suitable dimensions and an inner surface which combine with the wetting characteristics of the reagent to form a concave reagent meniscus suitable to reliably position a lens of immiscible liquid thereon. The lens so formed is centrally located by the concave shape of the meniscus. Preferably, the reagent dispenser further includes an integrally associated source of reagent.

Abstract: The present invention relates to apparatus and method for separating, by centrifugation, blood lymphocytes from other leukocytes in a blood sample. Small dense particles, either wetted or suspended in a physiological, hydrophilic medium, and a chemically inert hydrophobic barrier material are initially located in a suitable container. When the blood sample is added to the container, the particles are phagocytized by the monocytes and granulocytes, so as to increase their specific gravities. Upon centrifugation, the barrier material, whose specific gravity is only slightly greater than the specific gravity of the lymphocytes and less than the respective specific gravities of the phagocytic cells which have ingested particles and of the erythrocytes (red blood cells) in the blood sample, forms a rigid barrier therebetween, allowing harvesting of the lymphocytes, substantially free of contamination.

Abstract: Vitamin B.sub.12 in liquid samples, such as human serum or human plasma, is assayed by a competitive binding technique using intrinsic factor and certain labelled vitamin B.sub.12 derivatives. The labelled derivatives are formed from the (d)-monocarboxylic acid isomer of vitamin B.sub.12, which isomer is free from other monocarboxylic acid isomers (and derivatives thereof) of vitamin B.sub.12, by binding to the (d)-isomer, via the carboxylic group, a compound which is itself a label (e.g. an enzyme) or which comprises a label (e.g. a fluorophore), or to which a label is attached (e.g. a histidine ester to which .sup.125 I is attached). The labelled derivatives of the (d)-monocarboxylic acid of vitamin B.sub.12, free from other isomeric monocarboxylic acids and derivatives, are novel and constitute one aspect of the invention.

Abstract: A test-tube assembly and method for carrying out immunoassays. The apparatus features two independent components, the first having a series of test-tubes fixed to a support and equidistantly dependent therefrom, and the second having a base including magnets permanently fixed therein, the two components being releasably couplable to hold the lower ends of the test-tubes adjacent the magnets in the base.

Abstract: A particle counting assay for haptens (small non-protein monovalent substances having a molecular weight below 1500) comprises mixing a liquid sample (e.g. of human origin) containing the hapten, with finely divided inert particles bearing the same hapten (or a specific analogue thereof), an agglutinator such as RF or C1q, and a measured amount of antibody, which amount is insufficient to cause agglutination of all the particles. The amount of hapten is determinable by measuring the extent of the agglutination.

Abstract: New and improved apparatus and method for thorough, non-invasive mixing of a flowing fluid stream, either continuous or segmented, are provided and, as disclosed, are embodied in a mixing conduit which comprises a plurality of interconnected bends, which may be in the form of arcuate coils or sections, successive arcuate sections being operable to establish secondary flow patterns in differing orientations within the flowing fluid stream, or individual segments thereof. Such arcuate sections may be disposed in a same plane, if formed in serpentine fashion, or in non-parallel, preferably orthogonal planes, if formed in a tortuous fashion. Also, the arcuate sections, or a series thereof may be formed in stacked fashion and located in essentially parallel planes.

Abstract: In the immunoassay of antigens in liquids, a reaction mixture is formed containing the liquid under assay, labelled antigen, and a mixed binding reagent which contains an antigen-binding site and a label-binding site, the two sites being spaced apart in the reagent so that a single molecule of labelled antigen cannot bind to both sites. The label is one whose activity is changed upon binding to a label-binding site, and the amount of antigen in the original liquid sample is determined by measuring the activity of the label in the reaction mixture. A preferred label is a fluorophore. The mixed binding reagent preferably consists of two antibodies linked together.