Method and Apparatus for Processing and Analyzing Particles Extracted From Tangential Filtering

Abstract

A filter arrangement with a top element and a bottom element and a filter element therebetween captures oversized particles on the upper surface of the filter element and tangentially rinses these particles using an elution fluid to provide a concentration of particles in a relatively low volume of fluid for further analysis. A configuration using a slider valve may also be utilized. Additionally, an arrangement of supply and receiving containers may be used to minimize the number of containers required. A mass flow meter may be incorporated to measure the flow of elution fluid. Finally, a wash stage of the filtering process may be used to introduce stain onto the particles for further analysis, such as that associated with Gram staining and these stained particles may be further analyzed.

1 .- 27 . (canceled) 
     
     
         28 . Using a fluid/particle mixture and a filter element that captures oversized particles and allows undersized particles to pass through, a method for separating the particles from a fluid/particle mixture comprising the steps of:
 a) filtering the fluid/particle mixture through the filter element so that the oversized particles are deposited and entrapped on a top surface of the filter element;   b) tangentially wiping the top surface of the filter element with an elution fluid to displace the entrapped particles from the top surface of the filter; and   c) collecting the displaced particles and the elution fluid;   d) manually or automatically smearing the displaced particles upon a medium and thereafter gram staining the particles; and   e) analyzing the gram stained particles.   
     
     
         29 . The method according to  claim 28 , wherein analyzing the stained particles is achieved using a scanning microscope. 
     
     
         30 . The method according to  claim 28 , further including, after the step of filtering the fluid/particle mixture, of rinsing additional undersized particles through the filter element with a rinse liquid. 
     
     
         31 . The method according to  claim 28 , wherein the filter element has pores with openings between approximately 0.01 and 50 microns wide. 
     
     
         32 . The method according to  claim 31 , wherein the filter has a pore size of approximately 0.4 microns wide. 
     
     
         33 . The method according to  claim 28 , wherein the gram stain is crystal violet. 
     
     
         34 . The method according to  claim 28 , wherein the particles are automatically smeared using a specimen processor. 
     
     
         35 . The method according to  claim 28 , wherein filtering the fluid/particle mixture through the filter element is done using suction through the filter element. 
     
     
         36 . The method according to  claim 28 , wherein the particles are bacteria. 
     
     
         37 . The method according to  claim 28 , wherein the filter element is a polycarbonate-type filter element. 
     
     
         38 . The method according to  claim 28 , wherein the elution fluid is effervescent. 
     
     
         39 . The method according to  claim 28 , wherein the elution fluid contains a foaming agent.