Abstract: A method of analyzing the data provided by a fluorescent chemical sensor calculates a ratio based on the AC and DC components of the emission from the chemical sensor. This ratio, or the emission modulation, will change should bacterial growth be ongoing in the vial. The calculated ratio is compared to a desired value. The desired value is selected to focus the operation of the system into a high resolution area for the sensor. If the calculated and desired ratios differ, then the frequency of the excitation radiation is changed until the calculated and desired ratios are effectively equal. At that time the adjusted frequency is measured. By focusing the desired ratio into a high resolution area, and adjusting the frequency until the system reaches that ratio one ensures that all readings are performed at a high resolution area of the sensor. The adjusted frequency is utilized to provide an indication of whether the particular vial is experiencing bacterial growth.

Abstract: A test device provides an enclosed culture device for safe determination of the presence of a targeted microorganism. A test chamber is concentrically received within a culture chamber, and caps allow selective opening of one chamber without opening the other. A window in the test chamber allows selective flow of liquid between chambers, the window being so placed as to require particular manipulation of the chambers. The test chamber contains a culture medium and, through appropriate manipulation, a sample in the culture chamber is caused to wet the culture medium. The device is then incubated, and the sample in the culture chamber maintains high humidity in the test chamber because of the window. A pre-treatment vial is also provided so the sample can be treated before being placed into the culture chamber, to eliminate interfering organisms or the like.

Abstract: A system (10) and method of use for observation of microorganisms in a controlled environment is described. The system uses a diffusion gradient chamber (12) with reservoirs (24) which provide a compound or analyte (S) through a membrane (20) into a space in the chamber containing the microorganisms. The system preferably uses a camera (40) which records the observations of the microorganisms. The system enables study of microorganisms in gradients of compounds and the isolation of useful microorganisms.

Abstract: Disclosed are devices for amplifying a preselected polynucleotide in a sample by conducting a polynucleotide amplification reaction. The devices are provided with a substrate microfabricated to include a polynucleotide amplification reaction chamber, having at least one cross-sectional dimension of about 0.1 to 1000 .mu.m. The device also includes at least one port in fluid communication with the reaction chamber, for introducing a sample to the chamber, for venting the chamber when necessary, and, optionally, for removing products or waste material from the device. The reaction chamber may be provided with reagents required for amplification of a preselected polynucleotide. The device also may include means for thermally regulating the contents of the reaction chamber, to amplify a preselected polynucleotide. Preferably, the reaction chamber is fabricated with a high surface to volume ratio, to facilitate thermal regulation.

Abstract: A method for the flow cytometric assay of an analyte using monodisperse particles carrying a specific binding partner, the analyte and binding partner being selected from the group consisting of (a) antigen and specific antibody, (b) hormone and hormone receptor, (c) hapten and antihapten, (d) polynucleotide and polynucleotide binding protein, (e) biotin and avidin or streptavidin, (f) enzyme and enzyme cofactor and (g) lectin and specific carbohydrate, and the method comprising the steps of adding to the aqueous sample a predetermined amount of particles and a predeterminded amount of a labelled ligand having affinity for the analyte or the binding partner and detecting and quantifying the resulting labelled ligand-carrying particles by a flow cytometer, the method using a pair of different particle types which are distinguishable from each other by the flow cytometer and which respectively carry binding partners having the same specificity but different binding affinity for the analyte and independently but

Abstract: The invention relates to a perfusion chamber 1, a mixing device 21, and a cover slip holder 6 for use together with the perfusion chamber 1. The bottom of the cover slip holder 6 is provided with cross-located grooves 11, 12, 13-1 for installing cover slips 14, 15, 16-1, and in which the cover slips 14, 15, 16-1 are positioned in comparison to each other in such a way that the cross-sectional area of the flow channel 4 is constricted unilaterally, for simulation of thrombogenesis in human blood vessels with stenosis. The bottom of the perfusion chamber 1, in the measure chamber 7, can also have an elevation into the flow channel 4 in the measure chamber 7 which together with the recessed cover slip holder bottom produces a bilateral constriction of the cross-sectional area of the measure chamber 7. A mixing device 21 is connected to the system upstream of the perfusion chamber 1 and produces homogeneous mixing of solutions added to the blood flow.

Abstract: The present invention relates to an homogeneous immunoassay system for the determination of an antibody or an antigen in a sample which consists of an interferometric signal emitted from an infrared source, a waveguide coated with an antibody or an antigen and having at least one region immersed in an aqueous sample, whereby the corresponding antigen or antibody can be complexed on the surface of the waveguide, a detector adapted to measure the interferometric signal after its propagation through the waveguide, and a measuring device to take the Fourier transform of the interferometric signal for determining the degree of attenuation of the interferometric signal at a wavelength corresponding to an absorption characteristic of an infrared label incorporated into the antigen-antibody complex, whereby determining the concentration of antigen or antibody in the sample.

Abstract: This invention relates to a method for biodetection and identification of antibiotic susceptibility tested in bacteria by cerating spectrum against target cells and comparing them.

Abstract: A method of assaying for an analyte in a fluid sample comprises detecting the presence of the analyte by determining the resulting change in refractive index at a solid optical surface in contact with the sample, which change is caused by the analyte involving or influencing the binding or release of a refractive index-enhancing species to or from, respectively, the optical surface. Determination is performed with light having a wavelength at or near the maximum of the negative derivative of the absorptivity with respect to wavelength of the refractive index-enhancing species to obtain maximum sensitivity.

Abstract: An apparatus for counting microorganism colonies on at least one disposable microorganism culturing medium having a substantially planar substrate. The apparatus is adapted to interact with a cassette holding a number of similar substrates at once. The apparatus includes an imaging device capable of detecting colonies on the substantially planar substrate, a cassette positioning device for moving the cassette so that the substrates supported within the cassette are moved sequentially into a predetermined position relative to the imaging device, and an ejecting device for ejecting a substantially planar substrate in turn from the cassette when that substrate is in the predetermined position from the cassette and into an imaging position adjacent the imaging device. Suitable cassettes and a method for counting colonies on substrates supported within a cassette are also disclosed.

Abstract: An alstonine composition is useful as a selective marker of tumor cells and/or of chromosomal aberrations, and for the detection thereof by measurement of fluorescence at about 375 nm. Thus, an alstonine preparation can be used as a diagnostic agent designed for selective detection of tumoral diseases, and in cytogenetics. The diagnostic agent has application in preoperative, peroperative and postoperative diagnoses.

Abstract: A whole blood glucose test strip for measuring glucose in an unmeasured whole blood sample which does not require removal of excess sample, and which is adapted for use in a reflectance reading apparatus which measures reflectance at about 635 nm and about 700 nm, the test strip comprising a handle having an aperture defined therein; and a porous, hydrophilic matrix disposed over the aperture such that one surface of the matrix is exposed to the atmosphere adjacent to one side of the strip and the other surface of the matrix is exposed to the atmosphere on the other side of the strip through the aperture, one of the surfaces being an upper sample receiving surface adapted to receive the whole blood sample on one side of the matrix and the second of the surfaces being a lower testing surface from which diffuse reflected light is measurable, the testing surface being opposite to the sample receiving surface.

Abstract: An improved surface plasmon resonance detector, capable of recovering a desired eluted ligate, permits the isolation and characterization of novel ligates and ligands.

Abstract: A system for assaying a fluid sample, typically employing a fluorescent tag, the system comprising a lens capable of focussing both excitation and fluorescent radiation, a fluid-flow conducting conduit being provided in the lens extending transversely of the optical axis of and through the focal region of the latter. One or more mechanical screens are disposed adjacent to the focal region in the conduit to arrest passage of beads as a function of bead diameter. The beads, precoated with at least a moiety of a ligand/conjugate complex, e.g. a specific-binding ligand, are preferably substantially transparent to both the excitation and fluorescent radiation.

Abstract: A temperature controlled culture dish apparatus is disclosed. The apparatus consists of a culture dish assembly, a stage insert assembly, and a temperature controller. The culture dish assembly has a culture dish bottom which is manufactured from glass of high optical transmissivity coated with a transparent electrically conductive material. The biological specimen is grown directly on the culture dish bottom. The culture dish assembly is then placed into a recess in the stage insert assembly for microscopic examination. The biological specimen is not disrupted or transferred from the culture dish in which it was grown for purposes of examination. Power wires on the floor of the recess in the stage insert assembly contact bus bars on the transparent electrically conductive coating material. A thermistor on the floor of the recess in the stage insert assembly contacts the bottom of the culture dish bottom.

Abstract: Device for detecting the presence or amount of an analyte of interest, comprising a reflective solid, optical support and a label capable of generating fluorescent signal upon excitation with a suitable light source wherein said support comprises an attachment layer comprising a chemical selected from the group consisting of dendrimers, star polymers, molecular self-assembling polymers, polymeric siloxanes, and film forming latexes wherein the support provides an enhanced level of exciting photons to the immobilized fluorescent label compound, and wherein the support also increases the capture of fluorescent signal.

Abstract: Method for producing an optical assay device having a substrate and one or more optical layers, an attachment layer and a receptive layer, including the step of spin coating an anti-reflective layer or an attachment layer.

Abstract: The present invention is a process and apparatus for metal ion detection. The process of the invention has the steps of (1) disposing, in an analyte medium, a macromolecule suitable for selective complexation with the target metal ion species; (2) disposing, in the analyte medium, an appropriate photoluminescent indicator that will emit in a measurably different manner when bound to the metallomacromolecule complex, compared with its unbound state; (3) exciting the photoluminescent indicator species; and (4) monitoring the emission of the photoluminescent indicator species to detect changes in its emission.

Abstract: A multi-purpose on-line or field-portable system and method for monitoring the presence and concentration of selected antigen-antibody reactions singly or in combination that result from the presence of specific microorganisms or free antigens present or suspended in aqueous solutions, during a given time period. The detection system comprises a detection column and two sensors mounted around the J-shaped detection column. Each sensor consists of an electromagnetic radiation source and an appropriate detector for the electromagnetic radiation. The reacted analyte tends to accumulate at the sensor located in the curve of the J-shaped detection column. The lower sensor continually nulls against the upper sensor to subtract any optical effects due to non-reactants in the aqueous process or environmental stream. The response from the detector sensors drive an electric circuit, which provides an output signal.

Abstract: Method for detecting the presence or amount of an analyte of interest in a sample by providing a substrate having an optically active surface exhibiting a first color in response to light impinging thereon, and exhibiting a second color comprising a combination of wavelengths of light different from the first color or comprising an intensity of at least one wavelength of light different from the first color, in response to the light when the analyte is present on the surface in an amount selected from any one of 0.1 nM, 0.1 ng/ml, 50 fg, 2.times.10.sup.3 organisms comprising the analyte; and contacting the optically active surface with a sample potentially comprising the analyte of interest under conditions in which the analyte can interact with the optically active surface to cause the optically active surface to exhibit the second color when the analyte is present.

Abstract: The presence of trace materials in a sample is detected using both macroscopic and microscopic properties. A detector includes a light source and an optical resonator. The light source may be located either inside the resonance cavity of the resonator or outside the cavity, in which case it may be a semi-conductor such as a semi-conductor laser or a superluminescent diode. The detector also includes at least one reflective member that has a total internal reflection (TIR) surface and may be a passive device or an active gain element. Light from the light source is preferably focussed onto a single point of reflection on the TIR surface. The test sample is positioned within the evanescent field region of the TIR surface. Optical changes arising within the evanescent field region, such as excitation of fluorescence in the sample, changes in its refractive index, and changes in the resonant frequency of the optical resonator, are then detected.

Abstract: An evanescent wave system and method including an optical sensor for use in assaying a reference material and at least one molecular species or analyte in a test medium or test sample for diagnostic and other applicable purposes. The sensor includes a waveguide for propagating a radiation input along its length. The radiation input causes evanescent electromagnetic waves that are capable of stimulating output emissions that are indicative of a reference material and of one or more molecular species or analytes. By comparing the emission(s) indicative of the reference material to the emission indicative of the presence of the molecular species or analyte, the presence and concentration of the molecule in the sample can be determined. The reference material provides for normalization and/or calibration of the system.

Abstract: The present invention describes an apparatus for detecting biological activities in a large number of blood culture containers. The containers are placed in a plurality of wells arranged in concentric rows on a turntable that is rotated about a central axis. Each well is designed to receive and hold one of a plurality of sealable containers inserted base first, with each container having optical sensing means for sensing microorganisms therein and a bar code pattern attached thereto for identification purposes. Each well has an opening in its base to allow a sensor station to monitor a fluorescence chemical sensor in each container to determine whether there is microorganism growth within the container. Prior to inserting each container into a well on the turntable, a culture medium and blood specimen are introduced into the container and the bar code is scanned to identify the container.

Abstract: A method for measuring the presence of traces of substance in air by providing in a cuvette a substrate reacting with the substance by changing its opacity, passing at a defined flow rate air from the air body to be checked through the substrate, measuring the development of opacity. A portable apparatus comprises a housing (1, 101) holding a cuvette (131) containing a substrate (3, 103), an inlet tube (28) leading to the bottom of the cuvette, a pump (13) sucking air from the cuvette through a flow monitor (138) controlling the pump, a spectrophotometer lamp (19, 119) and a photo-diode (20) on opposite sides of the cuvette (131), a monitor monitoring the level (4, 104) of the substrate in the cuvette, and a monitor (23, 123) monitoring the temperature of the substrate, a computer (24) receiving signals from the photodiode (20), the level monitor, and the temperature monitor to calculate a temperature and level compensated indication of the substrate opacity.

Abstract: Methods and apparatus for evanescent light fluoroimmunoassays are disclosed. The apparatus employs a planar waveguide and optionally has multi-well features and improved evanescent field intensity. The preferred biosensor and assay method have the capture molecules immobilized to the waveguide surface by site-specific coupling chemistry. Additionally, the coatings used to immobilize the capture molecules provide reduced non-specific protein adsorption.

Abstract: Changes in specified indicia of colony growth in the early stages of incubation are monitored to provide the early detection and enumeration of colonies in the growth medium. Data from images collected at different times is processed to enhance the detection of subtle changes in the specified indicia of colony growth and provide an early indication of the number of colonies present in the growth medium.

Abstract: A method for determining one member of an enzyme-substrate pair (the analyte), comprises bringing the members of the pair into contact so as to form, directly or indirectly, a soluble reaction product at or adjacent the surface of an optical waveguide biosensor. The biosensor is preferably a resonant optical biosensor based on the principle of frustrated total reflection.

Abstract: Instrument configured and arranged to detect the presence or amount of an analyte of interest on the substrate of an optical device. The instrument has a source of linearly polarized, monochromatic light positioned at an angle other than Brewster's angle relative to the substrate; and an analyzer positioned at the same angle relative to the substrate at a location suitable for detecting reflected polarized light from the substrate; wherein the analyzer is configured and arranged to approximately maximize the change in intensity of the light reflected from the substrate that is transmitted through the analyzer when a change in mass occurs at the substrate relative to an unreacted surface.

Abstract: Apparatus for measuring liquid aldehydes includes a liquid sample pouring mechanism for dividing a liquid sample which contains aldehydes into a formaldehyde measuring liquid sample and a total aldehyde measuring liquid sample and pouring the liquids separately from each other; a formaldehyde measuring mechanism for measuring the liquid formaldehyde in the formaldehyde measuring liquid sample; a total aldehyde measuring mechanism for measuring the liquid aldehydes in the total aldehyde measuring liquid sample; and a formaldehyde ratio calculating mechanism for calculating the ratio of the formaldehyde to the total aldehyde from the results of the measurements of the respective aldehyde measuring mechanisms.

Abstract: Methods for functionalizing sensing surfaces to be used in systems for measuring simultaneously several properties of one biomolecule as well as for simultaneously measuring the concentrations of a plurality of biomolecules in a sample. The invention furthermore also relates to sensor units containing such surfaces, to the use thereof for surface characterization of biomolecules, and to a reagent kit for functionalization of sensing surfaces.

Abstract: A system for analyzing sample liquids using dry reagents which is particularly suitable for the determination of clinical parameters. The system includes an analysis instrument containing the individually sealed test elements to carry out an analytical test. Shape and nature of the test elements were designed to match the analysis system. The system is particularly suitable for analyses where the available test elements exhibit a low storage stability when brought into contact with the environment.

Abstract: Methods and apparatus for detecting biological activity within a sample are disclosed. The present invention provides a combination of a first and a second infrared light source arranged on the side of a sample vial, and a first and a second narrow-band infrared detector similarly arranged on the side of the vial approximately opposite the sources. The disclosed arrangement cancels the sources of error while measuring the carbon dioxide content of the headspace gas above the sample. In operation, the present invention sequentially measures the photocurrents generated at each detector with no source turned on, with the first source turned on, and with the second source turned on and the first source turned off. The CO.sub.2 absorption coefficient of the vial headspace gas is then calculated based on the photocurrents measured. This present invention allows compensation for source aging, detector aging, and vial wall thickness changes.

Abstract: Device for detecting the presence or amount of an analyte of interest, having a substrate possessing an optically active surface which exhibits a first color in response to light impinging thereon, and exhibits a second color comprising a combination of wavelengths of light different from the first color or comprising an intensity of at least one wavelength of light different from the first color, in response to the light when the analyte is present on the surface of any amount selected from 0.1 nM, 0.1 ng/ml, 50 fg, and 2.times.10.sup.3 organisms comprising the analyte.

Abstract: A microorganism detecting apparatus comprising a fluorescence microscope section which is furnished with a motor-driven stage for placing thereon a microorganism sample subjected to fluorescent staining, and a light source portion for projecting excitation light of predetermined wavelength on the sample; a detection section which detects and photoelectrically converts fluorescence of specified wavelength from the microorganism sample at a position posterior to the microscope section; a filter unit which limits the band of frequencies ascribable to noise in relation to an electric signal from the detection section; a signal processor which reads the output value of the band-limited signal from the detection section, and which processes the read output value; and an automatic inspection section which drives the stage so as to permit the microorganism sample to be scanned over its whole area, and which stores each signal detection part in the sample so as to permit a fluorescent substance at the part to be verif

Abstract: A method of and an apparatus for measuring a specimen by the use of fluorescence light which has the step of dyeing the specimen with a fluorescence dye, the step of applying light to the dyed specimen and exciting the fluorescence dye, and the step of detecting fluorescence light from the excited specimen within a period which does not substantially overlap with the period of the application, and which can accurately detect the excited desired fluorescence light.

Abstract: A method of assaying for a ligand in a sample involves incubating the sample in contact with a specific binding partner for the ligand carried on one surface of an optical structure, irradiating the structure at a suitable angle or range of angles to the normal such that the resonance and/or total internal reflection of the radiation occurs within the optical structure and/or the layer of specific binding partner, and analyzing the radiation in order to determine whether, and if desired the extent to which and/or rate at which the generated radiation and/or optical characteristics of the optical structure are altered by complex formation.

Abstract: The detection of bacterial growth or the performance of other interrogative processes in multiple sample vials is accomplished using a moving rack that selectively couples optical locations to an optical excitation and detection system. The apparatus includes a drive mechanism combining agitation of the culture vials with a sequential scanning of an array of optical fibers, preferably by a spectrophotometric excitation and detection system. Selection of each culture vial provides, for example, optical detection of bacterial growth by fluorescence or other spectrophotometric measurements. A rack for holding vials is preferably the only moving assembly, and requires no mechanical or electrical interconnection with the excitation and detection system for its operation.

Abstract: A pickled vegetables fermentation detector is the sensor for sensing kimchi curing which converts variables depending on the state of kimchi curing into an electric signal and is provided with an air bubble generator, gas collector and detector, in which the inside of the air bubble generator is divided into an upper compartment and lower compartment; gas generated in curing pickled vegetables is collected in the upper compartment to a predetermined quantity and gas is transported to the lower compartment at a predetermined pressure, and the main body of the lower compartment connected to one side of the upper compartment is composed of an air bubble homogeneity device expanded to the lower portion and inserted to a predetermined fluid in the inside of the lower compartment; one wall of a pair of oppositely disposed side walls is thicker than the other, and thickness of the walls is cut off at a predetermined height in the lower wall of both walls and a transparent panel is installed in the proximity of those

Abstract: Methods of glycosylation analysis are described in which a sample containing one or more specific oligosaccharide(s) (the analyte) is contacted with a surface on which is immobilized a glycosidase specific for the analyte and/or a specific binding partner for a product of the action of a glycosidase on the analyte. The surface may be the active surface of a biosensor, e.g., a biosensor based on the principle of frustrated total reflection.

Abstract: Device for detecting the presence or amount of an analyte of interest, having a substrate possessing an optically active surface which exhibits a first color in response to light impinging thereon, and exhibits a second color comprising a combination of wavelengths of light different from the first color or comprising an intensity of at least one wavelength of light different from the first color, in response to the light when the analyte is present on the surface in any amount selected from 0.1 nM, 0.1 ng/ml, 50 fg, and 2.times.10.sup.3 organisms comprising the analyte.

Abstract: The present invention is directed to coated substrates having a coating of biological macromolecules, preferably proteins, which are capable of being immobilized on a substrate surface and have a marker. These proteins usually are mutant proteins obtained by mutagenesis of the gene encoding a random positioning protein. When a mutant protein molecule is immobilized on the substrate, the marker of the mutant protein molecule is in a select spatial relationship with both the substrate and the markers of adjacent protein molecules. A substrate coated with an oriented layer of the mutant proteins exhibits improved or different properties when compared to a substrate having a randomly positioned layer of proteins thereon.

Abstract: An apparatus as provided for use in carrying out electrochemiluminescence test measurements. The apparatus includes a cell to contain an electrochemiluminescence sample fluid. A working electrode is provided within the cell and is coupled to a supply of electrical energy to apply the same to the sample fluid. A temperature effect adjustment system serves either to adjust a temperature of the electrochemiluminescent sample fluid so that it is within a predetermined range, or else adjusts an output signal representing light produced through electrochemiluminescence of the sample fluid based on the temperature of the sample fluid.

Abstract: A toxicity testing assay wherein a test sample is prepared with electrochromic dye and a living organism of the cladoceran order or other test organisms, and the sample is irradiated with alternately blue and yellow light to excite fluorescence. The successive groups of fluorescent emissions are then viewed at 90.degree. by a photomultiplier which develops equivalent alternate count outputs, and the count output is amplified and processed to develop data indicating (1) membrane potential of cells of the living organisms and (2) the total dye fluorescence which provides indication of deleterious effects to the organisms.

Abstract: A test device for evaluating microbial contamination of a liquid comprises a hollow container unit defining a first compartment for containing a nutrient for growing microorganisms and a second compartment for containing a contamination indicating coloring agent. The first compartment is filled with the liquid to be tested, which liquid mixes with the nutrient to grow the microorganisms during a predetermined period of time. During growth of the microorganisms, a sealing mechanism isolates the first and second compartments from each other. After the predetermined period of time has elapsed, the sealing mechanism is operated to establish communication between the first and second compartments to thereby mix the coloring agent from the second compartment with the liquid from the first compartment. In the presence of microorganisms, the coloring agent colors the liquid to indicate contamination thereof.

Abstract: This invention relates to analyte-responsive compositions and analyte detection methods using these compositions, and, more particularly, to such compositions based on potassium titanyl phosphate (KTP) and analogs thereof and to analyte detection methods based on piezoelectric and optical properties of materials.

Abstract: A change in voltage can be sensitively detected at a local part of a measured object. A set of laser medium and E-O probe are disposed between a pair of mirrors, a first one and a second one, forming a laser resonator. A linearly polarized light is emitted from the laser medium. The polarized light enters the E-O probe, and returns after being reflected by the second mirror. When a voltage is given to the E-O probe from the measured object, depending on the voltage, a refractive index of the E-O probe is changed, the light emitted from the E-O probe is ovally polarized, and a resonance status of the laser resonator then varies. Therefore, the light intensity emitted through the partially penetrating first mirror to the outside of the laser resonator corresponds to the voltage at the measured object in the proximity of the E-O probe. Consequently, a voltage distribution on the measured object such as IC with fine structures can be two-dimensionally detected.

Abstract: An apparatus for monitoring the presence of toxic substances in liquids is disclosed. The monitoring system is based on the use of luminescence systems such as those produced by luminescent microorganisms. The apparatus comprises a sampling device for obtaining a sample of the liquid, a device for providing a continuous culture of organisms or cells for supplying luminescence reagents and a detection device for detecting light emitted from mixture.

Abstract: A matrix coating suitable for use in a biosensor is provided. This matrix coating comprises a hydrogel bound to a surface and via which a desired ligand can be bound. This hydrogel is activated to contain charged groups for bringing about the concentration of biomolecules carrying an opposite charge to that of said charged groups, and reactive groups for covalently binding the biomolecules concentrated to the matrix coating.

Abstract: The present invention describes a method and apparatus for detecting microorganisms in a large number of blood culture vials using more than one microorganism detection principle for each vial. Two of such possible detection means includes the use of a fluorescent carbon dioxide sensor and scattered photon migration. The apparatus performs a logic linkage of the results of all the detection principles applied. Therefore, an enhanced recovery and an improved accuracy in detecting microorganisms is achieved.

Abstract: Methods and apparatus for detecting biological activities in a specimen such as blood are disclosed. The present invention provides a system whereby the intensity of light with a wavelength within the range of about 600 nm to 800 nm introduced into a sample at a first location is measured as it reemerges at a second location. A significant change in the intensity of the reemerging light indicates the presence of biological activity. Preferably, the intensity is also measured at a fourth location, or alternatively, a second light source is disposed at a third location to permit comparative intensity data to be collected. These data are useful in partially identifying the types of microorganisms present in the sample. In preferred embodiments, light emitting diodes are used as the light sources and multiplexed to a plurality of samples.