Automated platelet aggregation analysis using a digitizer.

A method of rapidly entering, reducing, and interpreting data collected in platelet aggregation studies has been developed. The standard aggregometer output is a chart recording of light transmittance (or optical density) as a function of time following the addition of an aggregating agent to a cuvette containing platelet-rich plasma or washed, suspended platelets. Two problems associated with aggregation studies are the proper calibration of the aggregometer and recorder to insure that comparisons of data can be made from experiment to experiment and the need to find a convenient way to analyze and summarize the data generated. In this method, the chart recorder is calibrated using reference cuvettes containing water or a suspension of latex beads of a known optical density. Since the analysis and interpretation of aggregation curves can be a time-consuming task, a standard digitizer has been interfaced to a computer, allowing the X,Y coordinates of the data, and, thus, the time-aggregation history of the sample, to be entered into the computer. The cursor of the digitizer is traced over the aggregation curve and the X,Y coordinates are transferred either at operator-selectable points or at fixed time intervals. A computer program (AGGPAD) calculates and stores several variables (e.g., sample baseline density, the magnitude of the aggregation, time to peak aggregation, maximum aggregation rate, and maximum deaggregation rate) that can be easily retrieved. The system reduces analysis time by a factor of five and allows for automated data storage and retrieval. The method is applicable to any computer and hardware costs are below $1000.00.