Abstract: A thin-wall centrifuge tube having multiple chambers for use in fluid sample investigation with an ultracentrifuge. More particularly, the multiple chamber ultracentrifuge tube can be used, for example, in lipoprotein separation. The ultracentrifuge tube may have two or more separate chambers which, subsequent to centrifugation, can be sealed from each other to retain the separated constituents of the sample under investigation. The chambers in the tube are joined by a constricted area which permits fluid communication between the chambers. The tube is designed to be used in conjunction with a support spacer adjacent the constriction in the tube so that the tube is properly supported during high speed centrifugation.