Abstract: A method for on-line assay in column chromatography of a property that requires appreciable time for sensitive measurement has the steps of separating the effluent into discrete fractions at equal time intervals, sequentially passing each fraction through each of a series of detectors, while preventing each fraction from mixing with another; and, for each fraction, calculating the assay from the information provided by each detector during the time interval the fraction passed through it.

Abstract: A device for protecting the user of a medical blood drawing instrument of the evacuated tube type from being pricked by the needle when removing it from the instrument. An end portion of the needle is threadly engaged in the instrument; a splined portion of the needle is disposed externally of the instrument; and the splined portion is normally engaged by a sheath protectively covering the needle before use is made of the needle. After removal of the sheath, use is made of the needle in a venipuncturing action. When the used needle is to be separated from the instrument, the needle with its splined portion is inserted into a passage of an upper member of the device. A cam mounted in the upper member is subject to being actuated by the user to engage the splined portion and hold the needle fast, so that the instrument may be turned relative to and unthreaded from the needle.

Abstract: An instrument for protecting the user of a medical syringe from being pricked by its needle when unsheathing or resheathing the needle. The instrument has an upper member releasably mounted atop a disposable container. A vertical passage through the upper member empties through a hole into the container. The passage has a coned entry mouth enabling the user to guide the sheathed needle end of a syringe into the passage.

Abstract: A method is described for kinetic measurement of enzyme activity bound to a solid matrix which improves both the sensitivity and speed of one immunoassay method. The immunoassay typically consists of reaction of the analyte with two specific antibodies, one fixed to the surface of a polymeric bead or wall of a test tube, the other added in solution and labeled by covalent coupling to an enzyme. By reaction between analyte and both antibodies, the enzyme-labeled antibody becomes fixed to the surface in a quantity proportional to the quantity of the analyte. After washing sufficiently to remove unreacted enzyme-labeled antibody, fixed enzyme activity is measured by incubation with a substrate and measurement of the rate of the reaction catalyzed. Fixation of the enzyme causes the reaction products to be localized near the surface. To measure the concentration of reactant or product repeatedly during the reaction, the solution must be mixed before each measurement, which can interfere with the measurement.

Abstract: There is disclosed a method for immunoassay and/or competitive binding assay, wherein an excess amount of unlabeled antigen is added after the start of the reaction between the labeled ligand, the unlabeled ligand, and the binding agent or antibody, to saturate or flood the antibody binding sites. This provides increased sensitivity allowing for more reliable and precise measurements of ligands including antigens than heretofore. The present method extends the scope of applicability of competitive binding technique for assay of hormones, drugs and other compounds.

Abstract: The reversed passive hemagglutination test (RPHA) for the detection of hepatitis B surface antigen (HB.sub.s Ag) is improved by the recognition that the speed of movement towards the periphery of a centrifugal field by immunologically aggregated solid phase support particles, increases proportionally with the amount of antigen present. It is further recognized that this dynamic study can be performed objectively and in an automated fashion by equipment such as the miniature centrifugal fast analyzer. The test performed in this manner and known as "reversed passive hemagglutination by minature centrifugal fast analysis" (RPHA/MCFA) is highly specific and eliminates the need for subsequent confirmational studies. Preliminary studies confirm a sensitivity comparable to other third generation tests.