Clinical tester wash and method

Abstract

A clinical tester has been described that includes a probe to aspirate a fluid. The probe is washed between aspirations to reduce carryover. The wash operation includes both an internal and an external wash, where the internal wash operation is terminated prior to terminating the external wash. In one embodiment, the probe wash can be implemented on an integrated clinical chemistry/immunoassay tester.

1 . A fluid tester comprising: 
 a probe having an interior region and an exterior surface, wherein the sample probe is used to selectively aspirate a fluid into the interior region;    a first wash mechanism coupled to the probe to dispense a wash fluid through the interior region of the probe for a first predetermined period; and    a second wash mechanism located to dispense the wash fluid on the exterior surface of the probe for a second predetermined period, wherein the second predetermined period extends beyond the first predetermined period.    
     
     
         2 . The fluid tester of  claim 1  wherein the aspirated fluid is 15 μL or less in volume and the second predetermined period is about one second and the second predetermined period extends about 0.1 second beyond the first predetermined period.  
     
     
         3 . The fluid tester of  claim 1  wherein the second wash mechanism is a cup having at least one wash fluid nozzle directed toward a center area of the cup.  
     
     
         4 . A clinical analyzer comprising: 
 a sample probe arm comprising a probe having an interior region and an exterior surface, wherein the probe is used to selectively aspirate a test sample into the interior region;    a sample wash mechanism coupled to the sample probe arm to dispense a sample wash fluid through the interior region of the probe for a first predetermined period; and    a sample wash station to receive the probe and dispense the sample wash fluid on the exterior surface of the probe for a second predetermined period, wherein the second predetermined period extends beyond the first predetermined period.    
     
     
         5 . The clinical analyzer of  claim 4  further comprising a reagent probe arm to aspirate a reagent.  
     
     
         6 . The clinical analyzer of  claim 5  further comprising: 
 a reagent wash mechanism coupled to the reagent probe arm to dispense a reagent wash fluid through an interior region of a reagent probe for a third predetermined period; and  
 a reagent wash station to receive the reagent probe and dispense the reagent wash fluid on the exterior surface of the reagent probe for a fourth predetermined period, wherein the fourth predetermined period extends beyond the third predetermined period.  
 
     
     
         7 . The clinical analyzer of  claim 4  wherein the second predetermined period is about one second and the second predetermined period extends about 0.1 second beyond the first predetermined period.  
     
     
         8 . The clinical analyzer of  claim 4  further comprising: 
 a sample transporter to transport a sample container containing a test fluid used to aspirate the test sample;  
 a chemistry analyzer coupled to sample the test fluid located on the sample transporter; and  
 an immunoassay analyzer coupled to sample the test fluid located on the sample transporter.  
 
     
     
         9 . The clinical analyzer of  claim 4  wherein the immunoassay analyzer comprises: 
 a second sample probe arm comprising a second probe having an interior region and an exterior surface, wherein the second probe is used to selectively aspirate a second test sample into the interior region of the second probe;  
 a second sample wash mechanism coupled to the second sample probe arm to dispense the sample wash fluid through the interior region of the second probe for a third predetermined period; and  
 a second sample wash station to receive the second probe and dispense the sample wash fluid on the exterior surface of the second sample probe for a fourth predetermined period, wherein the fourth predetermined period extends beyond the third predetermined period.  
 
     
     
         10 . A probe cleaning system comprising: 
 a wash pump coupled to dispense a wash fluid through an interior region of the probe for a first predetermined time period; and    a second wash pump located to dispense the wash fluid on an exterior surface of the probe for a second predetermined period, wherein the second predetermined period extends beyond the first predetermined period.    
     
     
         11 . The probe cleaning system of  claim 10  wherein a difference between a termination time of the first predetermined period and a termination time of the second predetermined time period is about ten percent (10%) of the second predetermined period.  
     
     
         12 . A method of cleaning a fluid probe comprising: 
 flushing an interior region of the fluid probe with a wash fluid for X seconds; and    simultaneously flushing an exterior surface of the fluid probe with the wash fluid for Y seconds, wherein Y is greater than X.    
     
     
         13 . The method of  claim 12  where a difference between a termination time of the interior region flush and a termination time of the exterior surface flush is about 0.1 Y.  
     
     
         14 . The method of  claim 13  where Y is approximately one second.  
     
     
         15 . A method of reducing sample carryover in an integrated chemistry and immunoassay analyzer comprising: 
 aspirating a first test sample from a first sample container using a probe;    depositing the first test sample into a reaction vessel;    performing a clinical analysis of the test sample;    washing the probe by pumping a wash fluid through an interior region of the probe and pumping the wash fluid on an exterior of the probe, wherein the pumping of the wash fluid is terminated from the interior region prior to terminating the pumping of the exterior; and    aspirating a second test sample from a second sample container using the probe.    
     
     
         16 . The method of  claim 15  wherein the pumping of the wash fluid on the exterior starts prior to pumping the wash fluid through the interior region.  
     
     
         17 . The method of  claim 16  wherein the wash fluid is pumped on the exterior for about one second.  
     
     
         18 . The method of  claim 17  wherein the pumping of the wash fluid through the interior region is terminated about 0.1 seconds prior to terminating the pumping of the wash fluid on the exterior.  
     
     
         19 . The method of  claim 15  further comprising: 
 aspirating a second test sample from the first sample container using a second probe;  
 depositing the second test sample into a second reaction vessel; and  
 performing an immunoassay analysis of the second test sample.  
 
     
     
         20 . The method of  claim 19  wherein the clinical analysis is either a chemistry or immunoassay analysis.  
     
     
         21 . A method of cleaning a probe comprising: 
 activating a first pump to pump a wash fluid through an interior region of the probe;    activating a second pump to pump the wash fluid onto an exterior region of the probe;    deactivating the first pump after a first predetermined time period; and    deactivating the second pump after a second predetermined time period, wherein the second predetermined time period is longer than the first predetermined time period.    
     
     
         22 . A method of washing a probe comprising: 
 determining an amount of fluid to be aspirated inside the probe; and    selecting an external wash profile in response to the amount of fluid aspirated inside the probe.    
     
     
         23 . The method of  claim 22  wherein the wash profile comprises a first wash sequence having both an internal and external probe wash, and an extended external wash if the amount of fluid aspirated exceeds a predetermined threshold.  
     
     
         24 . The method of  claim 23  wherein the extended external wash is about three times as long as the first wash sequence.  
     
     
         25 . A method of reducing carryover in a clinical tester as a result of external probe contamination comprising: 
 inserting the probe into a fluid;    determining an amount of fluid to be aspirated inside the probe;    dispensing the aspirated fluid;    washing the inside of the probe; and    selecting an external wash profile in response to the amount of fluid aspirated inside the fluid probe, wherein an extended external wash is provided if the amount of fluid aspirated exceeds a pre-determined amount.