Edna Colleen Probst

US Patent:

55261116, Jun 11, 1996

Filed:

Aug 31, 1993

Appl. No.:

8/114897

Inventors:

Rick L. Collins - Cicero IN
Martin T. Gerber - Carmel IN
Zindel H. Heller - Indianapolis IN
James L. Maxwell - Carmel IN
Edna C. Probst - Cedar Rapids IA
Loy M. Vail - Cicero IN
Stefan Weinert - Fortville IN
Morris J. Young - Indianapolis IN

Assignee:

Boehringer Mannheim Corporation - Indianapolis IN

International Classification:

G01N 3349
G06F15900

US Classification:

356 39

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. The coagulation characteristic is then calculated from the stored envelope values within the predetermined range of envelope values corresponding to the absolute maximum.