Blood coagulation analyzer

Abstract

One method and apparatus for analyzing clotting characteristics of a blood sample includes the use of a non-linear equation having coefficients capable of being related to the underlying clotting processes. The non-linear equation is curve fit to a waveform of a clotting sample to provide values for the coefficients of the non-linear function. Once the coefficients are obtained, an inference engine may be used to evaluate the non-linear relationship between the coefficients and factor concentrations within the blood sample. Advantageously, the waveform of the actual sample may be detrended to extract a residual oscillatory component to aid in the determination of initial coefficients for simplifying the curve fit operation. The non-linear equation may additionally be used for providing simulated clotting waveforms for testing clot analysis instruments. A residual oscillatory component may advantageously be extracted from the clotting signal. The oscillatory components may be used to provide a high quality clot time indicator for the sample. In addition, the oscillatory component may be used to correct for clot anomalies by correlating the frequency of the oscillatory to various physical characteristics of the blood clot. The oscillatory component may be used to provide initial estimates for values of the coefficients of the logistic. The logistic, because it represents knowledge as to the underlying chemistry of the clotting process, may also be used to provide initial estimates for coefficients of the logistic, and may also be used to enhance the accuracy of existing polynomial template clot analysis techniques. The logistic model may also be used to verify the operation of clot analysis tools.