Abstract: In combination, an instrument for determining a characteristic of a biological fluid or a control, and a cuvette for holding a sample of the biological fluid or control, the characteristic of which is to be determined. The instrument comprises a radiation-reflective surface, a first source for irradiating the surface, and a first detector for detecting radiation reflected from the surface. The cuvette has two opposed walls substantially transparent to the source radiation and reflected radiation. The first source and first detector are disposed adjacent a first one of the two opposed walls. The radiation reflective surface is disposed adjacent a second of the two opposed walls. A second source is provided for irradiating the surface. The first detector detects radiation from the second source reflected from the surface.

Abstract: In combination, an instrument for determining a characteristic of a biological fluid or a control, and a cuvette for holding a sample of the biological fluid or control, the characteristic of which is to be determined. The instrument comprises a radiation-reflective surface, a first source for irradiating the surface, and a first detector for detecting radiation reflected from the surface. The cuvette has two opposed walls substantially transparent to the source radiation and reflected radiation. The first source and first detector are disposed adjacent a first one of the two opposed walls. The radiation reflective surface is disposed adjacent a second of the two opposed walls. A second source is provided for irradiating the surface. The first detector detects radiation from the second source reflected from the surface.

Abstract: In combination, an instrument for determining a characteristic of a biological fluid or a control, and a cuvette for holding a sample of the biological fluid or control, the characteristic of which is to be determined. The instrument comprises a radiation-reflective surface, a first source for irradiating the surface, and a first detector for detecting radiation reflected from the surface. The cuvette has two opposed walls substantially transparent to the source radiation and reflected radiation. The first source and first detector are disposed adjacent a first one of the two opposed walls. The radiation reflective surface is disposed adjacent a second of the two opposed walls. A second source is provided for irradiating the surface. The first detector detects radiation from the second source reflected from the surface.

Abstract: An instrument for determining a characteristic of a biological fluid or a control includes a radiation-reflective surface, a first source for irradiating the surface, and a first detector for detecting radiation reflected from the surface. A cuvette for use with the instrument holds a sample of the biological fluid or control the characteristic of which is to be determined. The cuvette has two opposed walls substantially transparent to the source radiation and reflected radiation. The first source and first detector are disposed adjacent a first one of said two opposed walls and the radiation reflective surface is disposed adjacent a second of said two opposed walls.

Abstract: An instrument for determining a characteristic of a biological fluid or a control comprises a radiation-reflective surface, a first source for irradiating the surface, a first detector for detecting radiation reflected from the surface, and a mechanism for determining the characteristic based on the detected radiation. A slide holds a sample of the biological fluid or control the characteristic of which is to be determined. The slide has two opposed walls transparent to the radiation. The first source and first detector are disposed adjacent a first one of the two opposed walls and the radiation reflective surface is disposed adjacent a second of the two opposed walls. A system is provided for supplying power and regulating supplied power from one of multiple power sources to the instrument.

Abstract: An instrument for determining a characteristic of a biological fluid or a control comprises a radiation-reflective surface, a first source for irradiating the surface, a first detector for detecting radiation reflected from the surface, and a mechanism for determining the characteristic based on the detected radiation. A slide holds a sample of the biological fluid or control the characteristic of which is to be determined. The slide has two opposed walls transparent to the radiation. The first source and first detector are disposed adjacent a first one of the two opposed walls and the radiation reflective surface is disposed adjacent a second of the two opposed walls. A system is provided for supplying power and regulating supplied power from one of multiple power sources to the instrument.

Abstract: An instrument and a method for determining a characteristic of a biological fluid or control comprise providing a radiation-reflective surface, a source for irradiating the surface, a detector for detecting radiation reflected from the surface, and a cuvette for holding a sample of the biological fluid or control. The cuvette has two opposed walls substantially transparent to the source radiation and reflected radiation. The source and detector are disposed adjacent a first one of the two opposed walls and the radiation reflective surface is disposed adjacent the other wall. The method comprises detecting radiation from the source reflected from the surface using the radiation detector to determine a characteristic of the biological fluid or control.

Abstract: A method of immunizing the operation of an instrument which determines a characteristic of a biological fluid or a control against noise. The instrument includes a surface upon which a user deposits a sample of biological fluid or control the characteristic of which is to be determined. The instrument irradiates the sample and detects radiation from the sample to determine the characteristic.

Abstract: A method of determining whether a sample or a control has been applied to an instrument for measuring coagulation of a fluid by optically detecting when the fluid that has been applied to the instrument has passed a first and a second points, determining the flow time for the fluid between the two points, establishing a time threshold, and the flow time to the threshold to determining if the fluid is a sample or a control.

Abstract: A method for calculating a coagulation characteristic of a sample of blood, a blood fraction, or a control comprises generating an output signal indicative of coagulation of the sample, sampling the output signal at a sampling rate for a predetermined time to provide a plurality of sampled signal values, storing the sampled signal values, rectifying the stored sampled signal values to provide a plurality of envelope values, and storing the envelope values. The stored envelope values are examined in reverse time order to determine a slope of the envelope at each of the stored envelope values. All relative maxima in the stored envelope values are identified. A range of stored envelope values corresponding to each relative maximum is determined. The identified relative maxima are compared to locate an absolute maximum in the stored envelope values.

Abstract: An instrument and a method for determining a coagulation characteristic of blood, a blood fraction or a control comprise a radiation-reflective surface, a first source for irradiating the surface, and a first detector for detecting radiation reflected from the surface. A cuvette holds a sample of the blood, blood fraction or control the coagulation characteristic of which is to be determined. The cuvette has two opposed walls substantially transparent to the source radiation and reflected radiation. The first source and first detector are disposed adjacent a first one of the two opposed walls and the radiation reflective surface is disposed adjacent a second of the two opposed walls.