Baxter Travenol Laboratories, Inc.

Paolo Priarone

Eugene K Achter

Rodolfo R Rodriguez

Jerome C Kremen

Peter A St John

An improved nephelometer for immunochemical complex assay measures forward light scatter in samples. The angle of forward scatter, about 30.degree., is small enough to result in a large amount of forward scatter from the immunochemical complex particles which are to be assayed, whose size is of the order of the wave length of the light used in the optical system. Forward scattering from smaller particles, such as from molecules of buffer, antibody and serum, is constant during the course of a test, and is compensated for by the use of subtraction circuits which are readily and semiautomatically adjusted to subtract proper values, in accordance with the readings taken on standard or 'blank' samples of buffer, antibody and serum. Forward scattering from large particles, such as dust, is variable, and results in fluctuating signals, which are electrically processed to ignore the spurious peaks. The results of a test are displayed on a digital read out meter. Also described is a method of and protocol for immunochemical assay, whereby the amount of antigen originally present in a sample is determined by adding a known amount of antibody, and by assaying the 'blank' component ingredients and the resulting mixture.

Nephelometer having means semiautomatically canceling components from

The photometer is adapted for sensing radiation emitted by a chemical sample held in a cuvette received in a first compartment and includes a highly sensitive photomultiplier in a second compartment adjacent the first compartment for detecting fluorescent radiation emitted by the chemical sample and passing through an opening between the compartments. A mechanical protector assembly is provided for protecting the photomultiplier from ambient light and includes a movable light shield movable between a first position blocking the opening and a second position not blocking the opening. A knob is provided for moving the light shield to the first position to protect the photomultiplier from light entering from the first compartment when the first compartment is opened for insertion or removal of a cuvette, and for moving the light shield to the second position not blocking the opening to permit radiation emitted by the chemical sample to impinge upon the photomultiplier in the second compartment. The photometer also includes a mechanical interlocking assembly for ensuring that the first compartment cannot be opened unless the light shield is in the first position to prevent ambient light from entering the second compartment from the first compartment and reaching the photomultiplier.

Photomultiplier protector for a fluorometer

Nephelometer and nephelometer method for assaying immunochemical complex

An apparatus for incubating and analyzing blood samples while the samples are measured for oxygen association. The apparatus includes a controlled atmosphere chamber in which humidity, temperature and carbon dioxide may be maintained at a predetermined level while the level of oxygen concentration is varied. The samples are received in an apparatus which includes at least two slides having pockets therein for receiving the samples. The slides are arranged so that the specimens may be inserted in the holders, indexed to desired positions within the chamber for incubation and analysis, respectively, and removed from the chamber without affecting the controlled atmosphere within the chamber.

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West Hyattsville, MD, United States of America

Paolo Priarone