Filtering Blood

• US 20140042094A1
• Filed: 03/14/2013
• Published: 02/13/2014
• Est. Priority Date: 08/10/2012
• Status: Active Grant

• Current Assignee: Serumdpt Bioscience LLC
• Original Assignee: Jean I. Montagu
• Inventors: Montagu, Jean I., Bell, William, Montagu, Sasha
• Granted Patent: US 9,427,707 B2
• Time in Patent Office: Days
• US Class Current: 210/650
• CPC Class Codes: A61B 5/1411 by percutaneous method, e.g. by lancet
• CPC Class Codes: A61B 5/15003 for venous or arterial blood
• CPC Class Codes: A61B 5/150213 Venting means
• CPC Class Codes: A61B 5/150251 Collection chamber divided into at least two compartments, e.g. for division of samples injection syringes having more than one chamber A61M5/19; syringes for injection of two or more media A61M5/2448, A61M5/284; sample preparation for further analysis A61B5/150755
• CPC Class Codes: A61B 5/150351 Caps, stoppers or lids for sealing or closing a blood collection vessel or container, e.g. a test-tube or syringe barrel caps for bottles or containers in general B65D41/00
• CPC Class Codes: A61B 5/150389 Hollow piercing elements, e.g. canulas, needles, for piercing the skin
• CPC Class Codes: A61B 5/150503 Single-ended needles hollow piercing element tip design A61B5/150396, needle sets for catheters A61M25/06, needles for bringing media into the body A61M5/32
• CPC Class Codes: A61B 5/15074 Needle sets comprising wings, e.g. butterfly type, for ease of handling
• CPC Class Codes: A61B 5/150755 Blood sample preparation for further analysis, e.g. by separating blood components or by mixing
• CPC Class Codes: A61B 5/150946 Means for varying, regulating, indicating or limiting the speed or time of blood collection
• CPC Class Codes: A61B 5/150992 Blood sampling from a fluid line external to a patient, such as a catheter line, combined with an infusion line; blood sampling from indwelling needle sets, e.g. sealable ports, luer couplings, valves tubing connectors and couplings A61M39/00
• CPC Class Codes: A61B 5/153 Devices specially adapted for taking samples of venous or arterial blood, e.g. with syringes
• CPC Class Codes: A61B 5/154 Devices using pre-evacuated means
• CPC Class Codes: A61B 5/155 Devices specially adapted for continuous or multiple sampling, e.g. at predetermined intervals devices loaded with multiple lancets simultaneously A61B5/15146
• CPC Class Codes: A61M 1/0259 Apparatus for treatment of blood or blood constituents not otherwise provided for for agitating A61M1/025; for separating blood components present in distinct layers in a container A61M1/029
• CPC Class Codes: B01D 61/22 Controlling or regulating
• CPC Class Codes: B01D 71/04 Glass
• CPC Class Codes: G01N 33/48 Biological material, e.g. blood, urine G01N33/02, G01N33/26, G01N33/44, G01N33/46 take precedence; Haemocytometers counting blood corpuscules distributed over a surface by scanning the surface G06M11/02
• CPC Class Codes: G01N 33/491 by separating the blood components G01N15/05 takes precedence

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.

Claims

1. A filtering device for filtering blood to obtain serum or plasma in a container, the container having access at both ends, a filter located within the container, and a flow rate or pressure differential limiting control element or device, the limiting element or device located upstream of the filter.

2. The filtering device of claim 1 in which the container is partially evacuated.

3. The filtering device of claim 1 or 2 wherein the limiting control element or device is located outside the container.

4. The filtering device of claim 3 wherein the limiting control element or device is integral with a blood drawing needle assembly.

5. The filtering device of any of the foregoing claims wherein it is fitted with an entering flow rate limiting control element or device.

6. The filtering device of claim 1 wherein the container during operation is partially pressurized.

7. The filtering device of any of the foregoing claim 1, 2 or 6 wherein the limiting control element or device is located inside the container.

8. The filtering device of any of the foregoing claims wherein the limiting control element or device is a flow constriction element or device.

9. The filtering device of claim 8 wherein the flow constriction element or device is in the form of a pin hole or pin holes in a flow-blocking disk.

10. The filtering device of claim 8 wherein the flow constriction element or device is in the form of or comprises a selected length of capillary tubing.

11. The filtering device of claim 8 wherein the flow constriction element or device is in the form of or comprises a fine mesh or porous foam.

12. The filtering device of claim 8 wherein the flow constriction element or device is in the form of or comprises a passage defined by a screw like segment.

13. The filtering device of any of the foregoing claims wherein it has a limiting control element or device constructed to limit differential pressure across blood in the inlet side of the filter.

14. The filtering device of claim 13 wherein it has a limiting control element or device preceding the filter that limits entering flow-rate of whole blood.

15. The filtering device of any of the foregoing claims 1-13 wherein it has a limiting control element or device preceding the filter that defines entering pressure increase rate in whole blood.

16. The filtering device of any of the foregoing claims wherein it is portable or hand held, and includes a volume sized for blood drawn from a living being.

17. The filtering device of any of the foregoing claims wherein the material of the filter comprises glass microfibers and micro-porous membrane on a locating support.

18. The filtering device of any of the foregoing claims in which the container is a tube.

19. The filtering device of any of the foregoing claims having an access septum at the inlet end of the container or tube.

20. The filtering device of claim 19 having an access septum at the outlet end of the container or tube.

21. The filtering device of any of the foregoing claims 1-19 having, at the outlet end of the container or tube, a removable element in the form of an end-plug with a serum or plasma holding cavity.

22. The filtering device of any of the preceding claims including a volume pre-evacuated for drawing blood from a source.

23. The filtering device of claim 22 wherein the volume is pre-evacuated for drawing blood from a living being.

24. The filtering device of any of the foregoing claims constructed for controlling the incoming blood flow rate into a container or tube holding a filter in its central region such that the rate of increase of the pressure differential between the two sides of the filter stays below 30 mmHg per second.

25. The filtering device of claim 24 constructed to limit rate of increase to stay below 20 mmHG per second.

26. The filtering device of any of the foregoing claims constructed, by the axial position of the filter in the container or tube, for controlling the rate of increase of the pressure differential between the sides of the filter to stay below 30 mmHg per second.

27. The filtering device of claim 26 constructed to limit rate of increase of pressure differential to stay below 20 mmHg per second.

28. The filtering device of any of the foregoing claims 1 to 5 wherein the filtering device is pre-evacuated to induce flow of whole blood into the device, and constructed to define incoming blood flow rate into the volume at the inlet side of the filter to increase the pressure differential across the filter at a rate below 30 mmHg per second.

29. The filtering device of claim 30 constructed to limit rate of increase of pressure differential to stay below 20 mmHg per second.

30. The filtering device of any of the claims 24-29 in which the container is a tube and the pressure differential is between the ends of the tube.

31. The filtering device of claim 24, 26 or 28 as dependent on claim 1 or claim 17 or 21 as dependent on claim 1 wherein the limiting control element or device is an insertion of a compressible closed cell volume.

32. The filtering device of claim 1 following blood collection, constructed to be-pressurized by manual action of the user to produce pressure on collected blood to force the blood through the control element or device, and through the filter, to a vented collector.

33. The filtering device of claim 32 adapted for use with a first tubular member which is a pre-evacuated blood collection member, the device comprising a member pre-fitted in shape to receive the first tubular member and to be moved relative to the first tubular member to produce positive pressure, preceding an internal whole blood flow constriction element.

34. A method of obtaining blood serum or plasma using the filtering device of any of the foregoing claims 1-33.

35. The method of claim 34 conducted in the manner that the pressure differential across the filter is limited to below 30 mmHg per second.

36. The method of claim 35 conducted in the manner that the pressure differential across the filter is limited to below 20 mmHg per second.

37. The device of claim 1 in which the flow rate through the filter is approximately 2 to 10 cc per minute.

38. The device of claim 37 in which the flow rate is between 3 to 6 cc per minute.

39. The device of claim 37 constructed to produce a volume of between about 1 to 2 cc filtrate.

40. The device of claim 37 constructed to produce a volume of about 1.5 cc filtrate.

41. The device of claim 37 in which the limiting control element or device is a tubular element between ½

inch and 4 inches in length and has an internal diameter between about 0.008 and 0.013 inch.

42. The method of using the device of any of the claims 37-41.