Systems and methods of fluidic sample processing

• US 8,158,430 B1
• Filed: 08/06/2008
• Issued: 04/17/2012
• Est. Priority Date: 08/06/2007
• Status: Active Grant

• Current Assignee: Labrador Diagnostics LLC (SoftBank Group Corp.)
• Original Assignee: Theranos Incorporated
• Inventors: Roy, Shaunak, Gibbons, Ian, Ku, Edmond, Dang, Thanh, Burd, Tammy, Holmes, Elizabeth A., Takahashi, Malissa, Vollmer, Adam
• Primary Examiner(s): Yang, N. C.
• Application Number:
  US12/221,816
• Time in Patent Office: 1,350 Days
• Field of Search: None
• US Class Current: 436/16
• CPC Class Codes: G01N 2201/12746 Calibration values determination
• CPC Class Codes: G01N 27/06 of a liquid involving electrolysis G01N27/26
• CPC Class Codes: G01N 27/07 Construction of measuring vessels; Electrodes therefor
• CPC Class Codes: G01N 2800/52 Predicting or monitoring the response to treatment, e.g. for selection of therapy based on assay results in personalised medicine; Prognosis
• CPC Class Codes: G01N 33/49 Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80
• CPC Class Codes: G01N 33/5302 Apparatus specially adapted for immunological test procedures
• CPC Class Codes: G01N 33/5304 Reaction vessels, e.g. agglutination plates for solid-phase systems G01N33/543
• CPC Class Codes: G01N 33/86 involving blood coagulating time or factors, or their receptors
• CPC Class Codes: G01N 35/1002 Reagent dispensers
• CPC Class Codes: Y10S 435/973 Simultaneous determination of more than one analyte
• CPC Class Codes: Y10S 436/809 Multifield plates or multicontainer arrays
• CPC Class Codes: Y10T 436/106664 Blood serum or blood plasma standard or control

Abstract

The present invention provides fluidic devices and systems that allow detection of analytes from a biological fluid. The methods and devices are particularly useful for providing point-of-care testing for a variety of medical applications.

Claims

1. A method of calculating an apparent dilution ratio utilized in diluting a blood sample for running a blood test, comprising:

a) providing a plasma sample derived from a diluted blood sample;

b) measuring conductivity of the plasma sample; and

c) comparing the measured conductivity to a set of predetermined values showing relationship of conductivity values and dilution ratios that are employed to dilute a blood sample, thereby calculating the apparent dilution ratio utilized in diluting the blood sample.

2. The method of claim 1, wherein the blood sample is diluted prior to running the blood test.

3. The method of claim 1, wherein the plasma sample derived from a diluted blood sample is substantially free of red blood cells.

4. The method of claim 1, wherein conductivity of the plasma sample is inversely proportional to the apparent dilution ratio.

5. The method of claim 1, wherein the measuring of the conductivity of the plasma sample is performed using at least two electrodes spaced at different locations.

6. The method of claim 5, wherein the electrodes are formed of stainless steel.

7. The method of claim 5, wherein the electrodes are spaced apart by 5 mm to 20 mm.

8. The method of claim 1, wherein an AC voltage is applied to the plasma sample.

9. The method of claim 8, wherein a relationship between a current induced by the AC voltage applied and the conductivity of the plasma sample is determined.

10. The method of claim 9, wherein the measured conductivity is amplified, reshaped, buffered, and/or sent to a microprocessor that outputs a DC voltage correlated to the measured conductivity.

11. The method of claim 1, wherein the blood sample has a volume from about 1 uL to about 500 uL.

12. The method of claim 1, wherein the predetermined values form a substantially linear calibration curve.

13. The method of claim 1, wherein the temperature of the plasma sample is fixed.

14. The method of claim 1, wherein the conductivity is measured with a calibration unit contained in a device that also collects the blood sample.