Abstract: A method for measuring the fluorescent lifetime of an unknown fluorescent sample, such as a biological liquid, without the requirement of manual intervention or a separate reference standard. An energetic light beam having its low energy component filtered out is shined on the sample. An optical detector is positioned such that the intensity of the components of the light beam reflected from the sample reaching the detector is substantially minimized but light remitted and/or fluoresced by the sample does reach the detector with non-trivial intensity. Errors arising from the electronic components of the system, such as RFI and D.C. offset errors, are isolated and minimized by positioning an opaque filter between the sample and the detector and measuring the resulting signal. The resulting baseline measurement data is stored for later error subtraction.

Abstract: The present invention relates to a dry control cartridge for providing a plurality of voltage and impedance inputs to an electrochemical analysis instrument for verification of its proper functioning. The dry control cartridge includes a battery and a plurality of electrical circuits for providing a plurality of predetermined voltage and impedance outputs. The dry control cartridge is adapted for insertion into an electrochemical analysis device using probe electrodes to measure microvolt-range potential differences, appropriate to the input ranges inherent in the instrument. By comparing the measured voltage and impedance inputs to the predetermined outputs of the cartridge, verification of the instrument's proper functioning and accuracy may be made.

Abstract: A method and apparatus for detecting proper strip insertion into an optical reflectance meter. An electrical or electromagnetic device within the optical reflectance meter launches a signal when a test strip is inserted therein. The test strip which is designed for use in such a meter contains a material which enhances the coupling of the signal to a receiver within the meter. The meter then receives the signal and will not produce reading until a signal of a proper level is received. Use of the meter and special test strip of the present invention comprises a more cost effective system for detection of proper test strip insertion which is not dependent upon clean optics as in prior art devices. The present invention therefore ensures reliable protection of strip insertion with the ability to distinguish not only whether the test strip has been inserted incorrectly by the user, but also whether the test strip was designed for use with the meter into which it has been inserted.

Abstract: A method and apparatus for measuring the heart rate of a patient. In one embodiment the apparatus includes a hollow bell mounted on a diaphragm. A transducer element is also positioned therein to receive sound transmitted through the diaphragm, convert the sounds into electrical impulses, and transmit the electrical impulses to a microprocessor. The electrical impulses have real-time wave patterns corresponding to the real-time wave patterns of the original sounds. The microprocessor performs mathematical operations on wave pattern data conveyed by the electrical impulses to determine a numerical value corresponding to the frequency of the wave patterns. This numerical value is sent to a digital output and displayed thereon.

Abstract: A reflector for improving the signal of spectrophotometer, the reflector comprising a truncated cone having a reflective inner surface and a conical axis, the truncated cone open at a larger axial end thereof, open at a smaller axial end thereof, and having an opening in the cone surface. The reflector returns specularly scattered light back to the surface of a sample, and therefore enhances the amount of collected light.

Abstract: The present invention relates to a method for passively determining the application of a sample fluid on an analyte strip using measurement of ambient light passing through the strip. Sample fluid, such as whole blood, is applied to a reagent matrix and the amount of ambient light transmitted through the matrix is periodically measured both before and after application of the sample fluid. A step increase of the transmitted light reading occurs after hydration of the strip, and the occurrence of this step increase is used to start a predetermined incubation period. At the expiration of the incubation period, another light transmission measurement is made which is indicative of an analyte concentration in the sample fluid (such as glucose concentration in a whole blood sample).

Abstract: An optical system for measuring the reflectance of flat strips having potentially optically non-uniform surfaces. In one embodiment the systems includes an array of discrete light sources, wherein each light source is driven by its own individual current, such that the pattern reflected onto a photodector is substantially uniform in intensity.

Abstract: A method for determining the application of a sample fluid on an analyte strip using first and second derivatives. Sample fluid, such as whole blood, is applied to a reagent matrix and sensor readings, such as reflectance readings or current readings, are taken of the fluid/reagent combination. The first and second derivatives of the sensor readings are calculated. A predetermined incubation time period is begun at either a local minimum in the first derivative or a local maximum following a local minimum in the second derivative data. At the expiration of the incubation period, another sensor reading is taken which is indicative of an analyte concentration in the sample fluid (such as glucose concentration in a whole blood sample).

Abstract: A method to compensate for lamp spectrum shift, comprises exposing a first detector to a first light from a lamp, thereby generating a first signal indicative of intensity of said first light; exposing a second detector to a wavelength (.lambda.) of a second light from said lamp, thereby generating a second signal indicative of intensity of said wavelength of said second light, after said second light has interacted with a sample; determining a new color temperature (T.sub.1) of said first light using the following equationT.sub.1 =(F.sub.1 /A).sup.1/xwhere A=F.sub.i /(T.sub.i).sup.x,x=a color temperature exponent of said lamp, F.sub.1 =said first signal, F.sub.i =an initial reference signal, and T.sub.i =an initial color temperature corresponding to said initial reference signal; and determining a first compensated signal (I.sub.1) using the following equationI.sub.1 32 S.sub.1 /B.sub.1where ##EQU1## S1=said second signal, h=Planck's constant, c=speed of light in vacuum, and k=Boltzman constant.

Abstract: A method and apparatus for eliminating the effects of varying sample distance on optical measurements. In a first embodiment, a light source and a detector are both positioned in front of a measurement sample. A light source lens assembly focuses the light such that its focal point is behind the measurement sample, while a detector lens assembly focuses the light reflected from the measurement sample such that its focal point is in front of the measurement sample. Any movement of the measurement sample away from its nominal position does not affect the detector output because the effects of the source lens assembly and the detector lens assembly cancel each other. In a second embodiment, a light source and two detectors are positioned on one side off a measurement sample. The first detector is placed at a small angle relative to the sample normal, while the second detector is placed at a relatively large angle relative to the sample normal.

Abstract: A method and apparatus for detecting proper strip insertion into an optical reflectance meter. An electrical or electromagnetic device within the optical reflectance meter launches a signal when a test strip is inserted therein. The test strip which is designed for use in such a meter contains a material which enhances the coupling of the signal to a receiver within the meter. The meter then receives the signal and will not produce a reading until a signal of a proper level is received. Use of the meter and special test strip of the present invention comprises a more cost effective system for detection of proper test strip insertion which is not dependent upon clean optics as in prior art devices. The present invention therefore ensures reliable protection of strip insertion with the ability to distinguish not only whether the test strip has been inserted incorrectly by the user, but also whether the test strip was designed for use with the meter into which it has been inserted.