Filtering blood
First Claim
1. A filtering device for filtering blood to obtain serum or plasma in a container, comparing:
- a pre-evacuated container including inlet and outlet ends with access at both ends,a filter located within the container, anda 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 while still enabling continuous blood flow into said pre-evacuated container and after said capillary restriction blood flowing unimpeded within the container toward the filter substantially eliminating hemolysis associated with the filter.
3 Assignments
0 Petitions
Accused Products
Abstract
An independent blood filter device depends on flow geometry to deliver blood serum or plasma free of detrimental levels of hemoglobin. It depends critically on an upstream flow rate or pressure differential limiting control element or device that limits the rate of change of pressure differential across the filter element. Pre-evacuated versions can be used to simultaneously draw blood from a living being and provide pressure differential across the filter element between an evacuated collector and a supply end open to atmosphere. A unit pressurized by hand motion employs the external shape of a partially filled blood collection tube as a piston to produce pressure in advance of the control element or device to create the pressure differential across the filter element to a collector vented to atmosphere. The control element or device is disclosed in numerous forms, including specially sized flow constrictions and compliant arrangements.
-
Citations
32 Claims
-
1. A filtering device for filtering blood to obtain serum or plasma in a container, comparing:
-
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 while still enabling continuous blood flow into said pre-evacuated container and after said capillary restriction blood flowing unimpeded within the container toward the filter substantially eliminating hemolysis associated with the filter. - View Dependent Claims (2, 3, 6, 11, 12, 13, 14, 15, 16, 17, 18, 19, 26, 27, 28, 29, 30)
-
-
4. 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. - View Dependent Claims (5, 20, 21)
-
-
7. 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. - View Dependent Claims (8)
-
-
9. 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.
-
-
10. 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. - View Dependent Claims (22, 23, 24, 25, 31, 32)
-
Specification