Patent ID: 7074577
Filing Date: 2006-07-11
Classification: B01L,G01N,Y10S

Abstract:
1. A method of separating and axially expanding buffy coat constituents of a blood sample, comprising: introducing the blood sample into a flexible sample tube, the sample tube having an elongate sidewall having a first cross-sectional inner diameter; introducing an elongate rigid volume-occupying float into the flexible sample tube, said rigid float having a specific gravity intermediate that of red blood cells and plasma; said float comprising: centrifuging the sample tube to effect a density-based separation of the blood sample into discrete layers at a rotational speed that causes a resilient enlargement of the sidewall to a second diameter in response to centrifugal force, said second diameter being sufficiently large to permit axial movement of the float in the tube; moving said float into axial alignment with at least the buffy coat constituents of the blood sample in response to centrifugal forces produced in centrifuging the blood; and thereafter, reducing the rotational speed to cause the tube sidewall to return to said first diameter, thereby capturing the float and trapping the buffy coat constituents in the analysis area.