Blood processing systems and methods which optically derive the volume of platelets contained in a plasma constituent

A blood processing system comprising

• a separation chamber assembly operating to separate blood into constituents including a plasma constituent having an optical density,
• an outlet path for conveying a volume of the plasma constituent from the separation chamber assembly during a processing period, the volume of plasma constituent containing a platelet volume (PLT.sub.Vol)(in ml),
• a sensor assembly operating to detect the optical density of the plasma constituent in the outlet path during several sample intervals (n) within the processing period and generate for each sample interval a sampled opacity value (T.sub.(n)) expressing the detected optical density as a function of incremental plasma volume processed during the respective sample interval, and
• a processing element coupled to the sensor assembly including an element that is operable to sum the sampled opacity values (T.sub.(n)) over the processing period and generate an integrated opacity output .SIGMA.T that expresses the platelet volume (PLT.sub.Vol) in relation to the integrated opacity output (.SIGMA.T) as a linear plot having a y-intercept (a) and a slope (b) as follows:
• PLT.sub.Vol (ml)=a+b›.SIGMA.T!.

A blood processing method comprising

• separating blood into constituents including a plasma constituent containing platelets and having an optical density,
• conveying in an outlet path a volume of the separated plasma constituent during a processing period, the volume of separated plasma constituent containing a platelet volume,
• detecting the optical density of the plasma constituent in the outlet path during several sample intervals within the processing period,
• generating for each sample interval a sampled opacity value expressing the detected optical density as a function of incremental plasma volume processed during the respective sample interval,
• generating an integrated opacity value by summing the sampled opacity values over the processing period, and
• expressing the platelet volume based upon the integrated opacity value.

A blood processing system comprising

• a separation chamber assembly operating to separate blood into a platelet-rich plasma constituent containing platelets and having a first optical density, and then separates the platelet-rich plasma constituent into a platelet concentrate and a platelet-poor plasma constituent having a second optical density,
• a sensor assembly operating to detect the first optical density and generate a first output indicative of the first optical density,
• a sensor assembly operating to detect the second optical density and generate a second output indicative of the second optical density, and
• a processing element coupled to each sensor assembly including an element that is operable to calibrate the first output against the second output to derive a calibrated opacity value which reflects the opacity of the platelet-rich plasma constituent due solely to platelets contained therein, the processing element further including an element that is operable to integrate the calibrated opacity value relative to a volume of platelet-rich plasma constituent processed over a time interval and generate an integrated output that expresses volume of platelets contained in the platelet concentrate processed during the time interval.

A blood processing method comprising the steps of

• separating blood into a platelet-rich plasma constituent containing platelets and having a first optical density,
• separating the platelet-rich plasma constituent into a platelet concentrate and a platelet-poor plasma constituent having a second optical density,
• detecting the first optical density to generate a first output indicative of the first optical density,
• detecting the second optical density to generate a second output indicative of the second optical density,
• calibrating the first output against the second output to derive a calibrated opacity value which reflects the opacity of the platelet-rich plasma constituent due to platelets contained therein, and
• integrating the calibrated opacity value relative to a volume of platelet-rich plasma constituent processed over a time interval to generate an integrated output that expresses volume of platelets contained in the platelet concentrate processed during the time interval.