Patent ID: 6089078
Filing Date: 2000-07-18
Classification: G01N

Abstract:
A process for measuring samples of particles in suspension in a liquid in a particle response analyzing instrument comprising a cytometric flow cell head with a flow restriction or sensing zone for determining any changes in physical, optical or electrical properties of said liquid as said particles therein pass through said flow restriction or sensing zone, whereby the said suspension is injected by a pump into the head at an injection rate d that characterizes a variable measurement frequency, said head comprising a sensor, said particles being injected one at a time into the sensor, said sensor delivering a response when one particle is in said sensor, said response being significant when the frequency of measurements for the injected particle is comprised in a defined measurement frequency range known to correspond with optimum output response range, whereas responses for a sample comprise first responses and further responses and whereas results for a sample are generated by processing significant responses in said instrument, whereinif the first responses are significant, the measurements continue with the same injection rate d to get further responses, and conversely,if instead the first responses are not significant, the injection rate is modified to either plus or minus d'=d/k, where k is the injection rate direction coefficient, in order to obtain significant further responses by modifying said variable measurement frequency back within said defined measurement frequency range.