Filtering blood

A filtering device for filtering blood to obtain serum or plasma in a container, comprising:

• a pre-evacuated container including inlet and outlet ends with access at both ends,
• a filter located within the container, and
• a flow rate limiting control element located upstream of the filter and designed to limit pressure differential across the filter, the flow rate control element including capillary restriction for limiting blood flow and blood thereafter flowing unimpeded inside said container toward the filter, wherein the flow rate limiting element is constructed to provide for initial flow rate between 2 cc per minute and 10 cc per minute.

A filtering device for filtering blood to obtain serum or plasma in a container, comprising:

• a pre-evacuated container including inlet and outlet ends with access at both ends,
• a filter located within the container, and
• a flow rate limiting control element located upstream of the filter and designed to limit pressure differential across the filter, the flow rate control element including capillary restriction for limiting blood flow toward the filter, wherein said capillary restriction of the flow rate limiting element includes a channel between about 0.5 inches and 4 inches in length, and includes an internal diameter between about 0.008 inches and 0.013 inches.

A filtering device for filtering blood to obtain serum or plasma in a container, comprising:

• a pre-evacuated container including inlet and outlet ends with access at both ends,
• a filter located within the container, and
• a flow rate limiting control element located upstream of the filter and designed to limit pressure differential across the filter, the flow rate limiting control element including capillary restriction for limiting blood flow toward the filter and including a channel approximately 12 inches long.

A filtering device for filtering blood to obtain serum or plasma in a container, comprising:

• a pre-evacuated container including inlet and outlet ends with access at both ends,
• a filter located within the container, and
• a flow rate limiting control element located upstream of the filter and designed to limit pressure differential across the filter, the flow rate control element including capillary restriction for limiting blood flow flowing toward the filter and passively limiting increase of the pressure differential across the filter when blood enters said pre-evacuated container in order to substantially eliminate hemolysis associated with the filter.