Abstract: A problem in pulse oximetry is discriminating between arterial and non-arterial oxygen. Non-arterial oxygen can become detectable by an oximeter when a patient moves, obscuring the oximeter's measurement of arterial oxygen at critical times. Recent advances in pulse oximetry have made it possible to make the discrimination between arterial and non-arterial blood oxygen values. To allow manufacturers, hospitals, and medical researchers to evaluate the new oximetry technology, and evaluate oximeters which use it, new simulation technology is presented which can simulate simultaneous arterial and non-arterial blood oxygen on demand, with precision as to oxygen value, waveform amplitude, and waveform frequency. This invention provides the required simulation by double amplitude modulating the red and infra-red oximeter pulses.

Abstract: A method of distinguishing between strips for different assays in an automated instrument, wherein characteristics to which the instrument is sensitive are selectively introduced in microwells of individual microstrips which are pretreated with a specific antigen or antibody for a particular test. On each microstrip, the wells having the characteristic collectively define a multi-bit code which corresponds to a particular condition or disease to be tested for. The automated instrument reads the characteristic from the selected wells and thus determines what test is to be conducted. The marks may have optical, radioactive, luminescent, fluorescent, or magnetic characteristics, in accordance with the test to be conducted.

Abstract: A method and system for simulating living tissue which is to be monitored by a pulse oximeter that provides red and infrared light flashes, the system including structure for: converting the red and infrared light flashes of the pulse oximeter into electrical signals; modulating the converted electrical signals to provide modulated electrical signals; and converting the modulated electrical signals to light flashes and transmitting the converted light flashes to the pulse oximeter for detection so that the pulse oximeter responds to the converted light flashes as it would to light flashes modulated by a living tissue.

Abstract: A photometer for sensing the optical density of a plurality of liquids located in a microtray provided with a rectilinear array of wells is provided with a detent device for locating each well in alignment with the photodetector and a plurality of magnets associated with the microtray and a plurality of magnet sensors associated with the photodetector for providing signals indicative of the specific well in alignment with the photodetector. A carrier having two bar magnets disposed at right angles to each is provided for supporting the microtray with the two bar magnets disposed parallel to adjacent sides of the microtray. Two linear arrays of equally spaced magnet sensors extend outwardly from the location of the photodetector at right angles to each other and at right angles to the bar magnets, respectively.