Method for filtering a fluid sample using an in-line fluid filter for an automated analyzer

Abstract

A method for filtering a whole blood sample using a filter element constructed and arranged to block the passage of fibrous and particulate matter which may be present in a liquid sample, such as a whole blood sample, while allowing the blood cells to pass is disclosed. In one embodiment, the filter element is part of an in-line filter assembly which assembly may include two complementary mating components. One component may take the form of a coupling provided with a male threaded portion adapted to be received into and engage the female threaded portion of the complementary mating component. This complemnetary mating component may be another coupling or an analysis system component, such as a valve. Each complementary mating component is adapted to receive a liquid sample carrying conduit therethrough. The coupling is also adapted to receive a filter mount which holds a filter element constructed and arranged as discussed hereinabove. When the complementary mating components are assembled, their respective conduits and the filter element are brought into alignment and fluid tight seal. In an alterntive embodiment, the filter element is permanently retained in a section of conduit which is provided with appropriate connecting means to allow the conduit section to be readily removed from the apparatus when cleaning or replacement is desired.

We claim: 
     
       1. A method for filtering a .[.whole blood.]. .Iadd.fluid .Iaddend.sample comprising the steps of: a) flowing said .[.whole blood.]. .Iadd.fluid .Iaddend.through a filter arrangement which filter arrangement includes a generally cylindrical body portion having opposed first and second faces and provided with a multiplicity of passageways substantially parallel to the longitudinal axis of said body portion extending between said opposed first and second faces, said passageways constructed and arranged to entrap fibrous matter carried in the .[.whole blood.]. .Iadd.fluid .Iaddend.sample as the sample flows through said passageways from said first opposed face, said first and second opposed faces spaced apart a distance at least as great as the average length of said fibrous matter so that said fibrous matter will not extend beyond said second face and can be dislodged from said passageways by backflushing;   b) entrapping said fibrous matter within said filter arrangement; and   c) backflushing said filter arrangement to dislodge said entrapped fibrous matter from said passageways.   
     
     
       2. The method of claim 1 wherein said opposed faces are substantially parallel to each other, and substantially perpendicular to the longitudinal axis of said body portion. 
     
     
       3. The method of claim 1 wherein said opposed faces are both convex. 
     
     
       4. The method of claim 1 wherein the filter arrangement further includes: a. a first body component having an axial passage therethrough between opposite body ends;   b. a cavity in said first body component intermediate said ends;   c. a second body component having an axial passage, said first and second body components constructed and arranged to be releasably secured to each other whereby said axial passages are in fluid communication: and wherein said filter arrangement further includes a filter mount adapted to receive said generally cylindrical body portion, said filter mount received within said cavity. .Iadd.     
     
     
       5.  The method of claim 1, wherein said fluid sample is whole blood. .Iaddend..Iadd. 
     
     
       6.  An in-line filter for filtering elongated fibrous matter having a predetermined size from a fluid sample, said filter comprising a generally cylindrical body portion with a longitudinal axis, said body portion having a pair of opposed faces and a multiplicity of passageways extending through said body portion substantially parallel to the longitudinal axis and having opposite open ends at said opposed faces, said passageways being of a predetermined axial length to facilitate trapping of only one end portion of fibrous matter at one of said opposed faces when a fluid sample with the fibrous matter flows through said passageways from said one opposed face to the other opposed face, the open ends of said passageways at said one opposed face having rounded edges to eliminate sharp protuberances or burrs and permit the fibrous matter trapped at the open ends of said passageways at said one opposed face to be dislodged from said filter by backflushing. .Iaddend..Iadd. 
     
     
       7.  The in-line filter of claim 6 wherein said opposed faces are convex. .Iaddend..Iadd.8. The in-line filter of claim 6 wherein said body portion 
     
     
        is formed of glass. .Iaddend..Iadd.9.  The in-line filter of claim 6 wherein the body portion has a diameter of approximately 0.060 inches and an axial length of approximately 0.080 inches. .Iaddend..Iadd.10. The in-line filter of claim 9 wherein said passageways have a diameter of approximately 0.008 inches. .Iaddend..Iadd.11. The in-line filter of claim 10 wherein said body portion has nineteen of said passageways. .Iaddend.