Method for ascertaining interferants in small liquid samples in an automated clinical analyzer

• US 20070143063A1
• Filed: 12/19/2005
• Published: 06/21/2007
• Est. Priority Date: 12/19/2005
• Status: Active Grant

• Current Assignee: Siemens Healthcare Diagnostics Incorporated (Siemens AG)
• Original Assignee: Siemens Healthcare Diagnostics Incorporated (Siemens AG)
• Inventors: Kaplit, Michael
• Granted Patent: US 7,477,997 B2
• Time in Patent Office: Days
• US Class Current: 702/140
• CPC Class Codes: B01L 2200/146 Employing pressure sensors
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 3/021 Pipettes, i.e. with only one conduit for withdrawing and redistributing liquids
• CPC Class Codes: G01N 35/1016 Control of the volume dispensed or introduced
• CPC Class Codes: Y10T 436/11 Automated chemical analysis
• CPC Class Codes: Y10T 436/119163 with aspirator of claimed structure

Abstract

A liquid aspiration method which includes a method for determining the quality of the aspirated sample through mathematical analysis of the standard deviation of the residuals of the linear regression analysis of the aspiration pressure profile generated between the onset of actual aspiration and the end of actual aspiration and comparison of the results with predetermined known values.

Claims

1. A method for verifying the integrity of an aspiration process during which liquid is aspirated between a container and a pipette comprising the steps of:

determining the profile of an aspiration pressure curve representative of pressure within the pipette;

calculating a mathematical representation of the profile of the aspiration pressure curve; and

,

determining by numerical analysis whether the difference between the actual and the mathematical is less than a predetermined value.

2. The method of claim 1 wherein the aspiration pressure curve comprises only those pressure values between the onset of actual aspiration and the end of actual aspiration.

3. The method of claim 1 wherein the predetermined value is the standard deviation of the residuals of a linear regression analysis of an aspiration pressure curve measured on a sample known to have clots therein.

4. The method of claim 1 wherein the predetermined value is the standard deviation of the residuals of a linear regression analysis of an aspiration pressure curve measured on a sample known to be less than a desired aspiration volume.

5. The method of claim 2 further comprising confirming that the difference in pressure values at the onset of actual aspiration and at the end of actual aspiration fall within a predetermined range.

6. The method of claim 5 wherein the predetermined range is the range of pressure difference values at the onset of actual aspiration and at the end of actual aspiration determined by pressure difference values for distilled water liquid and mixed water-glycerol liquid.

7. A method for verifying the integrity of an aspiration process during which liquid is aspirated between a container and a pipette comprising the steps of:

determining the profile of an aspiration pressure curve representative of pressure within the pipette;

determining whether the pressure difference before aspiration and at the end of aspiration is within or outside a specific range;

if the pressure difference is within that specific range, calculating a linear regression analysis pressure of the profile of the aspiration pressure curve; and

,

determining by numerical analysis whether the difference between the actual and the mathematical is less than a predetermined value.

8. The method of claim 7 wherein the aspiration pressure curve comprises only those pressure values between the onset of actual aspiration and the end of actual aspiration.

9. The method of claim 7 wherein the predetermined value is the standard deviation of the residuals of a linear regression analysis of an aspiration pressure curve measured on a sample known to have clots therein.

10. The method of claim 7 wherein the predetermined value is the standard deviation of the residuals of a linear regression analysis of an aspiration pressure curve measured on a sample known to be less than a desired aspiration volume.

11. The method of claim 8 further comprising confirming that the difference in pressure values at the onset of actual aspiration and at the end of actual aspiration fall within a predetermined range.

12. The method of claim 11 wherein the predetermined range is the range of pressure difference values at the onset of actual aspiration and at the end of actual aspiration determined by pressure difference values for distilled water liquid and mixed water-glycerol liquid.