Quality control method

Abstract

A method of quality control to diagnose the cause of a malfunction of an instrument. The method uses measurements of the physical property of a sample to diagnose the cause of a malfunction of an instrument. The spatial position of a control product sample is analyzed. Alternatively, the spatial position of a statistically significant number of patient blood samples can be used. The method enables the monitoring of an instrument for problems associated with debris and noise caused by red cell lysis inefficiency; instrument reagents pump volume settings; instrument laser alignments; instrument gain settings; and flow noise caused by partial plugs, residual plugs or other flow problems. The method provides a more specific indication of the type and cause of an instrument malfunctioning than non specific flagging provided by prior art methods.

We claim:  
     
         1 . A method for using a hematology control product comprising: 
 a. placing a hematology control product in an instrument, said control product containing at least one leukocyte analog which has been derived from a blood cell which has been treated so that it is resistant to degradation by the lytic reagents used in the hematological test procedures, and the analog remains responsive to the reagents used in the performance of the instrument, and    b. analyzing the spatial position of the control product in an instrument, said analysis selected from at least one member of the group comprising: 
 (1) D.C. volume,  
 (2) RF size,  
 (3) opacity, and  
 (4) light scatter.  
   c. reporting the results of such measurement in an instrument to diagnose the cause of a malfunction of the instrument.    
     
     
         2 . The method of  claim 1 , wherein said control product comprises at least one neutrophil cell analog.  
     
     
         3 . The method of  claim 1 , wherein the measurement of said physical properties are selected from the group comprising DC MEAN, DC standard deviation, RLS MEAN, RLS standard deviation, opacity mean, opacity standard deviation, and COUNT RATIO, PEAK TO VALLEY RATIO, WHITE TIME and DAY TIME and combinations thereof.  
     
     
         4 . The method of  claim 3 , wherein said control product further comprises the addition of lysable red blood cells.  
     
     
         5 . The method of  claim 4 , which further comprises adding a lytic reagent in an amount effective to lyse any unfixed red blood cells that are in the hematological sample.  
     
     
         6 . The method of  claim 5 , wherein the instrument malfunction is selected from the group comprising instrument gain, debris and noise, instrument pump volume and instrument laser alignment and combinations thereof.  
     
     
         7 . The method of  claim 6  wherein the pump volume specification comprises lytic reagent volume.  
     
     
         8 . The method of  claim 6  wherein the pump volume specification comprises quench reagent volume.  
     
     
         9 . The method of  claim 6  wherein the instrument laser alignment specification comprises the X axes alignment.  
     
     
         10 . The method of  claim 3 , wherein the control product comprises at least three different white blood cell analogs.  
     
     
         11 . The method of  claim 10 , wherein the control product comprises at least four different white blood cell analogs.  
     
     
         12 . The method of  claim 11  wherein the hematology control product further comprises an aqueous solution of a plasma substance.  
     
     
         13 . The method of  claim 12 , wherein said plasma substance is selected from the group comprising cholesterol, cholesterol esters, lipoprotein cholesterol, lipoprotein cholesterol esters, cholesterol combined with phospholipids, cholesterol combined with albumin, cholesterol esters combined with albumin, lipoprotein cholesterol combined with phospholipids, lipoprotein cholesterol combined with albumin and mixtures thereof.  
     
     
         14 . The method of  claim 2  wherein the hematology control product comprises at least a neutrophil analog and a lymphocyte analog.  
     
     
         15 . The method of  claim 2  wherein the hematology control product is further combined with a latex particle.  
     
     
         16 . A method for using a hematology control product which contains at least one leukocyte analog population comprising: 
 a. placing a hematology control product in an instrument, said control product containing at least one leukocyte analog which has been derived from a blood cell which has been treated so that it is resistant to degradation by the lytic reagents used in the hematological test procedures, and the analog remains responsive to the performance of the instrument and wherein said control-product simulates at least one physical property of a human leukocyte said property selected from the group comprising: 
 (1) volume measured by D.C. current,  
 (2) high frequency (RF) size,  
 (3) opacity, and  
 (4) light scatter  
   b. measuring said physical properties of the control product; and,    c. reporting the results of such measurement in an instrument to diagnose the cause of an malfunction of the instrument.    
     
     
         17 . The method of  claim 16 , wherein said control product comprises at least one neutrophil cell analog.  
     
     
         18 . The method of  claim 16 , wherein the measurement of said physical properties are selected from the group comprising DC MEAN, DC standard deviation, LS MEAN, LS standard deviation, opacity mean, opacity standard deviation, and COUNT RATIO, PEAK TO VALLEY RATIO, WHITE TIME and DAY TIME and combinations thereof.  
     
     
         19 . The method of  claim 18 , wherein said control product further comprises the addition of lysable red blood cells.  
     
     
         20 . The method of  claim 19 , which further comprises adding a lytic reagent in an amount effective to lyse any unfixed red blood cells that are in the hematological sample.  
     
     
         21 . The method of  claim 20 , wherein the instrument malfunction is selected from the group comprising instrument gain, debris and noise, instrument pump volume and instrument laser alignment and combinations thereof.  
     
     
         22 . The method of  claim 21  wherein the pump volume specification comprises lytic reagent volume.  
     
     
         23 . The method of  claim 21  wherein the pump volume specification comprises quench reagent volume.  
     
     
         24 . The method of  claim 21  wherein the instrument laser alignment specification comprises the X axes alignment.  
     
     
         25 . The method of  claim 18 , wherein the control product comprises at least three different white blood cell analogs.  
     
     
         26 . The method of  claim 25 , wherein the control product comprises at least four different white blood cell analogs.  
     
     
         27 . The method of  claim 26  wherein the hematology control product further comprises an aqueous solution of a plasma substance.  
     
     
         28 . The method of  claim 27 , wherein said plasma substance is selected from the group comprising cholesterol, cholesterol esters, lipoprotein cholesterol, lipoprotein cholesterol esters, cholesterol combined with phospholipids, cholesterol combined with albumin, cholesterol esters combined with albumin, lipoprotein cholesterol combined with phospholipids, lipoprotein cholesterol combined with albumin and mixtures thereof.  
     
     
         29 . The method of  claim 28 , wherein said aqueous solution of plasma substance is in an amount effective to enable the differentiation of each of said white blood cell analogs relative to blood cell volume and light scatter reference points.  
     
     
         30 . The method of  claim 17  wherein the hematology control product is further combined with a latex particle.  
     
     
         31 . The method of  claim 17  wherein the hematology control product comprises at least a neutrophil analog and a lymphocyte analog.  
     
     
         32 . A method of quality control comprising: 
 a. analyzing the spatial position of a leukocyte subpopulation in a quantity of patient blood samples to obtain a statistically significant value of a measured parameter, said analysis selected from at least one member of the group comprising: 
 (1) D.C. volume,  
 (2) RF size,  
 (3) opacity, and  
 (4) light scatter.  
   b. reporting the results of such measurement in an instrument to diagnose the cause of a malfunction of the instrument.    
     
     
         33 . The method of  claim 32  wherein the malfunction is selected from at least one member the group comprising lysis debris and noise, instrument reagents pump volume settings, instrument laser alignments, instrument gain settings, flow rate inconsistency and combinations thereof.  
     
     
         34 . The method of  claim 32  wherein the patient blood sample has been subject to a lytic reagent.  
     
     
         35 . The method of  claim 32  wherein the measured parameter is selected from at least one member of the group comprising PEAK TO VALLEY RATIO, COUNT RATIO, WHITE TIME, DC Mean, DC Standard Deviation, Opacity Mean, Opacity Standard Deviation, RLS Mean, RLS Standard Deviation and combinations thereof.  
     
     
         36 . The method of  claim 35  wherein at least two measured parameter are used and one of the measured parameters is DC MEAN of a leukocyte population.  
     
     
         37 . The method of  claim 33  wherein the pump volume specification comprises lytic reagent volume.  
     
     
         38 . The method of  claim 33  wherein the pump volume specification comprises quench reagent volume.  
     
     
         39 . The method of  claim 33  wherein the instrument laser alignment specification comprises the X axes alignment.