Abstract: A device for controlling equipment includes a light projector adapted to project light onto a head of a living body, a light collecting device for collecting the light having passed through the head from the light projector, a light measuring device for measuring an intensity of the light collected by the light collecting device, a memory device for storing a previous history of changes of the intensity of the light measured by the light measuring device, a signal judging circuit for judging if both the intensity of the light measured by the light measuring device and the previous history of changes of the intensity of the light satisfy a predetermined condition, a display device for displaying the intensity of the light measured by the light measuring device and a result obtained by the signal judging circuit, and a control signal generating circuit for generating a control signal to be supplied to an external equipment if the predetermined condition is satisfied.

Abstract: An apparatus and a method whereby plasma integrity of plasma contained in a blood bag is rapidly and accurately assessed without compromising the sterility of the plasma, or destroying any of its components. This is achieved through spectral data which is used in a novel way so as to determine if a plasma specimen representative of plasma in a blood bag contains interferents and if so, to what extent. The apparatus and method analyse plasma contained in two bags whereby tubing connects the two bags. A lamp is used to irradiate the specimen, and a spectrophotometer is used to measure radiation from the specimen. The apparatus and method allow for determination where both the bags and tubings are translucent and contain writing on their surfaces (e.g., proprietary information), and the light is transmitted through the writings, plastic, and the plasma contained in the bag or tubing.

Abstract: Centrifuged material layer volumes are measured and quantified during centrifugation of the material layers. The material layers are differentially highlighted by means of one or more supravital fluorescent dyes or stains which are admixed with the sample being analyzed. This kinetic quantification procedure is particularly useful in performing differential blood cell and platelet counts. The blood sample is centrifuged while being subjected to an intense filtered strobed light source at two different wavelengths. At least one photometric cell layer compaction measurement is made in conjunction with the light flashes so as to record a degree of cell layer compaction as the sample is being centrifuged. In certain cases, after several successive cell layer compaction readings are derived, a compaction curve is identified and the ultimate degree of cell layer compaction is calculated from the derived compaction curve prior to the achievement of the ultimate degree of cell layer compaction.

Abstract: A sensor device for measuring a concentration of a substance within a sample comprises a sensor comprising an optical fiber portion having a first end and a second end, the second end having a tip portion attached thereto and an active material incorporated within the tip portion, the tip portion adapted to be inserted into a sample, the active material capable of interacting with a substance within a sample, a light source coupled to the first end of the sensor for emitting a beam of light into and through the sensor and into a sample, the emitted beam of light having a wavelength and the active material interacting with a substance within a sample to change the wavelength of the emitted beam of light to produce a reflected beam of light and the sensor for transmitting the reflected beam of light out of the second end thereof, an optical detector for receiving the reflected beam of light from the second end of the sensor for producing a signal indicative of the reflected beam of light, and a processor for re

Abstract: A method for quantifying the concentration of hemoglobin in a cell, and indicia of anemia, comprises determining the wavelength of the longitudinal mode of a liquid in a laser microcavity; determining the wavelength of the fundamental transverse mode of a red blood cell in the liquid in the laser microcavity; and determining if the cell is anemic from the difference between the wavelength of the longitudinal mode and the fundamental transverse mode. In addition to measuring hemoglobin, the invention includes a method using intracavity laser spectroscopy to measure the change in spectra as a function of time for measuring the influx of water into a red blood cell and the cell's subsequent rupture.

Abstract: A sensor device for measuring a concentration of a substance within a sample comprises a sensor comprising an optical fiber portion having a first end and a second end, the second end having a tip portion attached thereto and an active material incorporated within the tip portion, the tip portion adapted to be inserted into a sample, the active material capable of interacting with a substance within a sample, a light source coupled to the first end of the sensor for emitting a beam of light into and through the sensor and into a sample, the emitted beam of light having a wavelength and the active material interacting with a substance within a sample to change the wavelength of the emitted beam of light to produce a reflected beam of light and the sensor for transmitting the reflected beam of light out of the second end thereof, an optical detector for receiving the reflected beam of light from the second end of the sensor for producing a signal indicative of the reflected beam of light, and a processor for re

Abstract: A monitor to provide substantially real-time estimates of fluid absorption rate and tissue loss rate in a patient during a surgical procedure. The monitor estimates fluid source flow rates and waste fluid flow rates based on weight changes per unit time or direct reading fluid flow rate meters. Tissue loss flow rates are estimated based on tissue concentration measurable in waste irrigation fluid using an optical comparator, and are used to correct waste fluid flow rates. Correct waste fluid flow rates are used in turn to obtain estimated fluid absorption rates.

Abstract: An attachment is designed such that a concentration measuring apparatus is attachable to and detachable from it. Inside the leading end portion of the attachment, leading ends of two light guide members are provided opposite to each other so as to hold a micro cuvette mounted on the attachment. One light guide member guides light from a light source of the concentration measuring apparatus to subject matter in the micro cuvette while the other guides light from the subject matter to light receiving elements of the concentration measuring apparatus. The concentration measuring apparatus calculates a concentration of the subject matter based on respective outputs from the light receiving elements.

Abstract: A multi-parameter hematology analyzer and method are provided for in vitro determination of blood parameters. The analyzer apparatus includes a laser for transmitting light through a specimen container containing a minimally diluted blood sample. The light scattered by the constituents of the blood sample are scattered into a pattern which is recorded on a camera image. This image is then processed by image processing software and is used to establish specific blood parameters.

Abstract: The present invention comprises methods of determining the performance of an absorbance spectrometer, and, in particular, of CO-oximeters. The methods comprise measuring the absorbance spectrum of a quality control sample and comparing it to a standard spectrum of that quality control. Instrumental error will be the primary factor contributing to the observed difference. The present method also provides techniques for converting the instrumental error manifested in the difference between the measured and standard quality control spectra into blood concentration values comparable to that of real blood. Analysis of test samples on a spectrophotometer; and calibration of the spectrophotometer is also provided.

Abstract: A centrifuge network communication system for transmitting instructions to, and receiving data from, a plurality of centrifuge instruments using a central data controller. The central data controller transmits instructions to the centrifuge instruments in the form of discrete data packets, including (a) a centrifuge arbitration packet containing at least one command for a centrifuge instrument, (b) a command execution packet, commanding a centrifuge instrument that has previously received a centrifuge arbitration packet to execute the at least one command contained in the centrifuge arbitration packet, and (c) a transmit acknowledge packet commanding a centrifuge instrument that has previously received a command execution packet to transmit data generated in response to the centrifuge arbitration packet to the central data controller.

Abstract: A spectrometric technique is described for quantitatively determining the change in concentration of a substance which is contained in a medium which both absorbs and scatters spectroscopically interrogated radiation, and in particular to the specific case in which the change in concentration of the substance occurs in one spatially distinct region of the medium. The medium includes a plurality of such regions displaying potentially different absorption and scattering properties to the radiation. Specific applications are disclosed involving the noninvasive determination of changes in concentration of the substances oxyhemoglobin and deoxyhemoglobin and/or changes in the redox state of the substance cytochrome oxidase within the brain or skeletal muscle, and in cases where the brain or skeletal muscle is interrogated by radiation in the near-infrared part of the electromagnetic spectrum through intervening surface tissues, i.e.

Abstract: A novel method and reagent useful therein are cyanide-free and capable of providing a rapid indication, e.g., less than 30 seconds, of total hemoglobin in a blood sample, so as to find particular application in automated hematological instrumentation. The novel reagent comprises an ionic surfactant, a pH of at least about 11.3 and is free of ionic cyanide. The ionic surfactant itself can impart the required pH or a strong base independent of such surfactant may be included.

Abstract: A particle counting apparatus for counting a total particle counting value contained in a liquid sample comprising, a flow cell in which the liquid sample flows, a light source for irradiating a light beam to the sample liquid in the flow cell, a detector for detecting pulse-wise signal scattered from the particles by the irradiating of the light beam, and a computer for obtaining the total particle counting value contained in the liquid sample as a counting value measured when the top end of the liquid sample is irradiated with the light beam and the plural particles in the top end does not overlapped in the light beam, multiplied by a coefficient.

Abstract: A method and apparatus for determining the parameters (i.e., proportion, mean, and standard deviation) of constituent subpopulations within a sample population of particles which contains overlapping populations. The invention includes the use of the EM algorithm, an iterative process which estimates the probability that a particle belongs to any given overlapping subpopulation.

Abstract: An apparatus and process for accurately determining settling data for the settling of erythrocyte cells from a plasma fluid in a test specimen of blood. The apparatus includes a settling tube, a sensing assembly movably mounted proximate the settling tube. Preferably an infrared emitter and detector are provided in the sensing assembly, and a control assembly is provided which senses data at a high rate and is responsive to the sensed data to sample or store the time at which sensed reflectivity exceeds a threshold level. When the threshold is reached, data is sampled and the tracking head is moved by a very small step. This process is repeated to enable tracking of the descent of the separation boundary between the erythrocyte cells and plasma fluid. The apparatus senses changes in reflectivity of the erythrocyte portion of the specimen below and up to the separation boundary.

Abstract: A measuring apparatus of the present invention measures the constituent concentration of a specimen after loading into the apparatus a test piece having a test material which develops coloring as a result of a reaction with the constituents of a specimen. When the apparatus detects that the test piece having the test material has been loaded, it automatically begins to measure the constituent concentration of the specimen. That is, after the loading of the test piece is detected, a predetermined time period is measured. During this time measurement, the time period is displayed at a predetermined time interval. After the time measurement of this predetermined time period is terminated, the test material is irradiated with a light, and the intensity of the light from the test material is detected. The constituent concentration of the specimen applied to the test material can be determined on the basis of the reflected light intensity thus detected.

Abstract: A blood loss monitoring apparatus is disclosed. The system includes a tank having a solution which removes blood from blood containing materials which are deposited in the tank and also hemolyzes the blood. Blood and blood containing materials are deposited into the tank during surgery, and the volume of liquid in the tank as well as the hemoglobin concentration in the tank are then determined. From this information, the total amount of hemoglobin lost is determined, and by measuring the patient's hemoglobin level immediately prior to the surgery, the total amount of blood lost is then calculated. The amount of blood lost can be continuously monitored and updated throughout the course of the surgical procedure or operation.

Abstract: The degree of hemoglobin oxygenation in the blood vessels of the retina is etermined under conditions of dark-adaptation and light-adaptation by directing a beam of near-infrared light having a range of wavelengths from 700 to 100 nanometers at a blood vessel in the retina, measuring the intensity of the backscattered light from the blood vessel in the range from 700 to 800 nanometers at regularly spaced intervals of wavelength, such as 2 nanometers, and determining the degree of hemoglobin oxygenation by reference to a correlation between hemoglobin oxygen and light absorbance in the near-infrared spectral range.

Abstract: System and method for the localization of functional activity in the human brain during neurosurgery. The system includes an electronic flash illuminator for illuminating the surface of the exposed portion of the patient's brain, optical bandpass filters for sequentially illuminating the exposed brain surface with monochromatic light of a number of predetermined wavelengths, a positioning mechanism for rapid positioning of the optical filters in the path of illumination, a video camera for acquiring an image of the exposed brain surface during illumination with each wavelength of monochromatic light, a circuit for converting the linear output signal of the video camera into a logarithmic signal in video format, a digitizer and frame storage memory for digitizing the logarithmic video signal to obtain multiple two-dimensional matrices. Each matrix represents the magnitude of light reflected at a particular wavelength from a regular grid of points over the exposed brain surface.

Abstract: An apparatus and method for measuring the volume and hemoglobin concentration of individual red blood cells in a whole blood sample provides for isovolumetrically sphering the red blood cells of the sample using a sphering reagent and forming a stream of individual, spaced-apart cells sheathed in an electrolytic liquid in a flow chamber. The red blood cells in the stream are passed through a light scattering channel in which the intensity of light scattered by each cell into a preselected angular interval in the forward direction is measured. Each cell in the stream is also passed through a resistance pulse sizing aperture for measuring the volume of the cell.

Abstract: An apparatus and method for measuring a bodily constituent such as glucose or cholesterol by analyzing a sample taken from the body such as blood, saliva or urine. The sample is placed on a test strip inserted into the test block portion of the apparatus where the portion of the sample containing the constituent desired to be measured reacts with a chemical reagent. Products of this reaction have an absorbance/reflectance characteristic which is mathematically related to the concentration of the constituent in the bodily sample. The reflected light is absorbed by a photodiode and the output of the photodiode converted to a digital form where a microprocessor can calculate the concentration of the constituent using the mathematical relationship between the reflected light and concentration stored in memory means of the apparatus.

Abstract: A light beam having a first wavelength (.lambda..sub.1) is applied to the blood from a first light radiation section, while a light beam having a second wavelength (.lambda..sub.2) is applied from second and third light radiation sections different in positions from the first radiation section and from each other to the blood and the respective reflected-light intensity (I.sub.1, I.sub.2, I.sub.3) is detected. A first correction value (X) for correcting the reflected-light intensity ratio (I.sub.2 /I.sub.3) is calculated by a first correction value operation section (40) and a second correction value (C.sub.1) is calculated by a second correction value operation section (42) by use of this first correction value and the reflected-light intensity (I.sub.3). The reflected-light intensity ratio (I.sub.1 /I.sub.2) is corrected by use of this second correction value and an oxygen saturation in the blood is operated based on correlation function by use of the corrected reflected-light intensity ratio (R.sub.s).

Abstract: An automatic hematocrit reader wherein a sample of blood in a microhematocrit capillary tube is banded with a standing wave from an ultrasonic transducer. A light source and photocell combination is used to determine the relative thicknesses of the bands of red blood cells and the bands of plasma. The hematocrit of the sample of blood is electronically calculated from this data. A calibration strip is included so that the device is calibrated each time the hematocrit is determined. The device includes a mechanical interlock/eject system for the microhematocrit capillary tube and is specifically configured so that the operator does not handle or even touch the microhematocrit capillary tube.

Abstract: A method for the analysis of blood platelet aggregations consists in that concurrently two parameters are measured the mean intensity and the RMS deviation of intensity of the light flux which had been passed through a blood sample (I2) from said means intensity, which is caused by fluctuations of the amount of blood platelets or their aggregations in the optical channel (I0), which are used to find the mean radius and concentration of blood platelets in the blood sample (I2) being tested. The apparatus also comprises a source (6) of the light flux, a photoreceiver (I1), units (I7 and I9) to form the mean intensity and the RMS deviation of current intensity from the means intensity, and a unit (20) for determination of parameters of a blood platelet aggregation.

Abstract: An apparatus and method for making a photometric absorbance measurement of hemoglobin in a blood sample utilizing a reusable cuvette and an inexpensive photometer. The cuvette is a unitary plastic body having a flow-through slot of a predetermined height which allows an absorbance measurement to be made with an undiluted blood sample and which permits cleaning by inserting the body in a liquid cleaning solution. Two absorbance measurements are made, the first at a wavelength at which the absorbance of oxyhemoglobin and deoxyhemoglobin are approximately equal, near an isobestic point, and a second measurement at which these components absorb substantially no light. By making the first measurement near an absorbance minimum at about 510 nm, an absorbance measurement can be made with a relatively thick slot required for cleaning and with an undiluted blood sample and an inexpensive photometer.

Abstract: A method for determining the presence of an analyte in a fluid is described along with various components of an apparatus specifically designed to carry out the method. The method involves taking a reflectance reading from one surface of an inert porous matrix impregnated with a reagent that will interact with the analyte to produce a light-absorbing reaction product when the fluid being analyzed is applied to another surface and migrates through the matrix to the surface being read. Reflectance measurements are made at two separate wavelengths in order to eliminate interferences, and a timing circuit is triggered by an initial decrease in reflectance by the wetting of the surface whose reflectance is being measured by the fluid which passes through the inert matrix. The method and apparatus are particularly suitable for the measurement of glucose levels in blood without requiring separation of red blood cells from serum or plasma.

Abstract: In a fiber optical probe for measuring or sensing a reflectance spectrum, an illuminating light supplying optical fiber (1) and a light receiving optical fiber (2) are coupled in parallel to form a fiber bundle (3). A lens (4) is provided on sensing end surfaces of both types of fibers of the fiber bundle. The fiber bundle is inserted in a heat shrinkable polyethylene tube and the tube is shrunken by heat to form a coating jacket (6). The coating jacket extends beyond the end of the fiber bundle to cover the periphery of the lens, so that the lens is fixed to the fiber bundle.

Abstract: Method and apparatus for spectrophotometrically determining the concentration of a number of hemoglobin derivatives comprising at least deoxyhemoglobin and oxyhemoglobin or parameters derived from the concentration of individual hemoglobin derivatives, in particular the oxygen saturation fraction, in whole blood, in which light is transmitted to the blood under test, the modification on the light transmitted to the blood which the blood causes is determined at a number of individual wavelengths, and the concentrations (or the derived parameters) are determined on the basis of the light modification at the individual wavelengths and on the basis of predetermined coefficients representing the light absorption characteristics of each of the hemoglobin derivatives at each of the individual wavelengths, any error on the determination values due to turbidity being substantially compensated for by utilizing predetermined coefficients representing an absorption characteristic of turbidity at each of the wavelengths.

Abstract: A method and device are disclosed for the detection of the relative percentage of at least one light absorber in the blood stream of living tissue. The method and device are based upon the employment of a narrow band width amplifier and pulses of different wavelength light sources wherein the frequency of the pulses of the light sources are selected so that a large component of the signal falls within the frequency of the narrow band amplifier, so that there is reduced likelyhood of interference from extraneous electromagnetic waves.

Abstract: A photoelectric arrangement for the determination of a substance spectrally differently absorbing light in a specimen (1) comprising two alternately switched on light sources (2,3) of different wavelengths matched to the absorption maximum or minimum of the substance, two photoelectric receivers (5,6) arranged in such a manner with respect to the specimen that the one receiver (measuring receiver 5) receives light which traverses the specimen and the other receiver (reference receiver 6) receives light of the light sources directly and an electronic control and evaluation circuit following the photoelectric receivers and controlling the light sources for the determination of the different absorption typical for the substance at the two wavelengths, wherein the control and evaluation circuit comprises a light circuit (7,8,10,11a,11b) following the reference receiver (6) for determining light amounts transmitted by the light sources and defining the switchover instant for the light sources on reaching a predete

Abstract: Infrared sensitive indicator-dilution tracer concentration, specifically, 1,2 propanediol, can be optically measured in blood drawn from the systemic arterial system to indicate lung vascular function and transcapillary transport, i.e. pulmonary blood flow, extravascular lung water, transcapillary permeability-surface area, fluid filtration coefficients, etc. that may be helpful in diagnosing lung diseases, particularly Adult Respiratory Distress Syndrome (ARDS).

Abstract: A method and reagent useful therein are cyanide-free and capable of providing a rapid indication, e.g., less than 30 seconds, of total hemoglobin in a blood sample, so as to fine particular application in automated hematological instrumentation. The novel reagent comprises an ionic surfactant, a pH of at least about 11.3 and is free of ionic cyanide. The ionic surfactant itself can impart the required pH or a strong base independent of such surfactant may be included.

Abstract: The hematocrit of a volume of blood can be determined in real time without volume or flow rate limitations by sensing the diffusion of infrared light by the bloodstream. For this purpose, an infrared light beam is directed at a transparent cuvette through which the blood is conveyed, and a photodetector is mounted beside the cuvette at an angle such that the intersection of the light beam and of the principal sensitivity lobe of the detector is wholly spaced from the multiple scatter zone adjacent to the light source. The hematocrit signal produced by the photodetector can be corrected for the effect of oxygen saturation by providing an oxygen saturation signal, multiplying the hematocrit signal by a function of the oxygen saturation signal and using a look-up table to derive a linear true hematocrit signal. Means are also provided to compensate the detected hematocrit signal for the effects of temperature, drive current, and aging.

Abstract: In an exposure apparatus for manufacturing semiconductor devices, a pattern on a photomask is aligned with a plurality of patterns formed on a wafer in a manner that detects and corrects misalignment, including, inter alia, rotational errors, not only between a photomask and a wafer, but also between a photomask and individual chips formed on the wafer, so that pattern matching is attained with very high accuracy. Apparatus for achieving this result employs different arrangements of alignment marks together with optical systems and positional adjustment devices.

Abstract: Disclosed is a sample chamber which is particularly adapted to the spectrophotometric analysis of blood samples. The instrument of which the sample chamber is a part includes means for directing a beam of light through the sample fluid and means for analyzing the light emanating from the fluid. The sample chamber comprises a first transparent member having a flat surface. A surface of a prism is disposed adjacent to the flat surface of the first member, and a resilient gasket located between the prism and the first member seals off a region which forms the sample chamber. A spring on a door, which closes to a position adjacent to the prism, engages the hypotenuse surface thereof to force the prism against the first member and compress the resilient gasket. First and second holes through the prism intersect the first surface thereof at opposite sides of the chamber formed by the gasket to enable the sample fluid to flow through the chamber.

Abstract: Blood constituents such as red cells, white cells, and platelets are centrifuged into layers in a capillary tube and the true extent of one or more of the layers is measured photometrically. Each layer to be measured is optically scanned by a sequence of scanning operations with the actual extent of each layer traverse being recorded in a computer. After each layer has been completely circumferentially scanned and each traverse recorded, the computer determines the true average axial dimension for each layer and computes, through prior input, the actual constituent count for each constituent layer.

Abstract: A method for quantitatively determining the amount of hemoglobin in feces, urine or gastric juice comprising the steps of preparing a test sample of the feces, urine or gastric juice, converting the hemoglobin in the test sample to porphyrin with a converting reagent which is acidic and which has a reducing capacity sufficient to convert substantially all or a reproducible portion of the hemoglobin to porphyrin and determining the level of porphyrin in the test sample.

Abstract: A circuit arrangement for determining the characteristics of liquids and/or gases, in particular for determining the diverse parameters of blood. The equipment determines the ratio of the signals of the sensing element resp. of the signal converter at a double-light photometer and a reference, simultaneously performing constant or periodical testing, accordingly, the control of the whole measuring system can be ensured. Signal processing takes place by the expansion of series or cutoff point interpolating logarithm forming, by averaging; the system includes structural elements for performing adjustable error detection. The largest advantage of the circuit arrangement according to the invention lies in that the instabilities of the photometers of traditional construction may be eliminated, a higher measuring accuracy becomes possible, and by ensuring the testing possibilities, by performing a continuous self-control reliable measuring data are delivered.

Abstract: A compact, portable, clinical instrument dedicated to hemoglobin determination employs an L.E.D. light source with a peak output wavelength of about 553 nanometers and a yellow-blocking filter with a long wavelength cut-off not longer than about 565 nanometers. Thus, the relative amount of energy incident upon the blood sample in the 540 nm. hemoglobin absorption band is maximized. In addition to the L.E.D., the photodetector and the amplifying, inverting, log conversion, digital conversion, display and power supply regulation circuits are also exclusively solid-state. The display is of the reflective or liquid crystal type, and the power supply regulator is a sophisticated integrated circuit containing the equivalent of many discrete components. As a result, current consumption is minimized, and battery life and instrument accuracy are maximized. As an alternative illumination source, an infra-red L.E.D. can be employed, and the instrument is then capable of blood turbidity measurement.

Abstract: A test value corresponding to blood subsidence from a syllectogram is determined as a result of the effect of shearing forces on a blood sample, by ascertaining the slope of the test curve representing the syllectogram at a predetermined time beginning with or after the onset of the blood aggregation phase as the test value after:(a) sudden stoppage of the shearing; or(b) a transition to a continuous minor residual shearing.

Abstract: A photometric system for determining the absorbance ratio, in a sample, of two different wavelength lights. First and second lights, each having a different wavelength, are passed through the sample in alternation with each other. The radiation intensity from each light that has passed through the sample is detected. A comparator, up/down counter and digital to analog converter are coupled so that a scaling factor is derived which, when multiplied with an analog signal proportional to the intensity of the first light after it has passed through the sample, is equal to an analog signal proportional to the intensity of the second light after it has passed through the sample. The output of the counter comprises a digital word corresponding to the ratio of the absorbance ratio of the first light and the second light.

Abstract: A reagent for photometric determination of the hemoglobin content of blood, which produces a characteristic color upon addition of the blood sample, consisting of an aqueous alkaline solution comprising a water-soluble, non-ionic detergent, whereby all hemoglobin-derivatives occurring in the blood and hemederivatives are converted into a unitary end product having a distinct absorption maximum in the visible spectral range.

Abstract: A portable spectrophotometric apparatus and method therefor for measuring the percentage of carboxyhemoglobin (COHb) in blood. The apparatus comprises a spectrophotometer and wavelength selection filters for testing a reference sample having a hemolizing agent and sodium hyposulfite and a treated blood sample with the hemolizing agent and sodium hyposulfite and providing a two component COHb-Hb system for determining relative absorbance values of the two samples at light wavelengths of 420 nanometers and 432 nanometers, the wavelengths corresponding to respective peak absorbance of the components in the high absorbance Soret region on opposite sides of an isobestic point formed by the intersection of their respective absorbance-wavelength curves. The ratio of the derived relative values is compared against predetermined data to determine the percentage of carboxyhemoglobin in the blood.

Abstract: In a flow metering apparatus a bubble detector for detecting bubble formation in tubing subject to deformation from internal fluid pressure includes a light source and a light detector. The light detector is positioned on the opposite side of the tubing from the light source such that the light transmitted through the tubing to the detector is dependent on the presence of fluid in the tubing and on the shape of the lumen of the tubing. A control circuit responsive to the output of the detector interrupts operation of the metering apparatus when the light transmitted through the tubing falls below a predetermined minimum level. False interruptions resulting from deformation of the tubing by pressure changes in the fluid are prevented by forming members which engage the wall of the tubing adjacent the light source and light detector.

Abstract: Deoxygenation of a blood sample prior to determination of carbon monoxide hemoglobin is performed in a capillary tube containing a dry reducing agent. Ready for use capillary tubes having long storage life contain dry reducing agent and are sealed at both ends. Preferred capillary tubes contain mixture of reducing agent, pH buffer and anticoagulating agent present as a dry material on the interior tube wall.

Abstract: Photometric apparatus and method for determining the absorbance ratio, in a sample, of two different wavelength lights. A first light is given a reference intensity and is passed through the sample. A second light is passed through the sample and its intensity is varied so that the intensity of the second light that has passed through the sample is equal to the intensity of the first light that has passed through the sample. When these intensities are equal, the intensity of the second light is detected in a state wherein it has not passed through the sample, resulting in an equivalent to the ratio of the absorbance in the sample of the second light and the first light.

Abstract: A single instrument for photometrically determining hemoglobin content and electronically determining white blood cell count of a single sample suspension of blood. The instrument is provided with a calibration mode of operation independent of the run or normal operational mode of the instrument.A vacuum system is described where vacuum is generated during the operating cycle only at periods when vacuum is required with an adjustable volume vacuum chamber interposed in the vacuum system to assure proper vacuum levels.Carryover of one liquid to a next introduced second liquid in the test vessel is reduced by successive draining of said second liquid and reintroduction into said vessel of a replacement amount of said second liquid. The second liquid can be a sample of rinse liquid.An hydraulic system is described as operating in conjunction with the pneumatic or vacuum system.

Abstract: A method of reducing scattered light during photometric measurements, especially during the photometric measurement of haemoglobin and a reagent for the performance of the method. To a suspension which is ready for a measurement operation there is admixed an additive which reduces the difference between the refractive index of the suspension and the mean refractive index of the suspended phase. The reagent for the photometric determination of the haemoglobin comprises a lysing agent, means for modifying the refractive index, means for stabilizing the leukocytes and a solvent. The reagent is admixed as an additive to a suspension of blood particles in an isotonic solvent.

Abstract: This invention encompasses a standard for determining glycosylated hemoglobin comprising a mixture of hemoglobin or methemoglobin and about 1% to 25% of the 2,4-dinitrophenyl derivative of hemoglobin or methemoglobin wherein a 2,4-dinitrophenyl group blocks the allosteric binding site of hemoglobin or methemoglobin.