a manipulative laboratory device for transferring biological fluid from one or more primary containers to an associated secondary set of containers through a disposable closed compartment system . the compartment system allows for greatly simplified decanting procedures , for example , in pouring off serum samples in blood analyses . the transfer device is preferably of transparent plastic material , and allows for complete isolation among respective samples and selective transfer of controlled volumes of biological fluid when combined with a pump , through means to apply equal volumes of pressurized gas to each of the compartments . the transfer device allows , serum , for example , to be held and filtered during transfer , while maintaining the serum within a closed compartment to reduce the risk of hepatitis and similar infectious transmissions to operating personnel . in combinations with the disposable transfer device , a pressurization device and rack constructions are provided to facilitate gang handling of a plurality of biological fluid specimens , in one operation .