Method and apparatus for detection of multiple analytes

Abstract

In some embodiments, an apparatus analyzes the composition of bodily fluid. The apparatus comprises a fluid handling network including a patient end configured to maintain fluid communication with a bodily fluid in a patient and at least one pump intermittently operable to draw a sample of bodily fluid from the patient. The apparatus further comprises a fluid analyzer positioned to analyze at least a portion of the sample and measure the presence of two or more analytes. Also disclosed is a method for analyzing the composition of a bodily fluid in a patient. The method comprises drawing a sample of the bodily fluid of the patient through a fluid handling network configured to maintain fluid communication with a bodily fluid in a patient. The method further comprises analyzing the at least a portion of the sample in a fluid analyzer to estimate the concentration of two or more analytes in the sample.

1 . A body fluid analysis apparatus comprising:
 a fluid handling network including a patient end configured to maintain fluid communication with a bodily fluid in a patient;   a valve system in operative engagement with the fluid handling network, the valve system having an infusion mode in which the valve system is operable to deliver infusion fluid to the patient through the patient end, and a sample draw mode in which the valve system is operable to draw a sample of the bodily fluid from the patient through the patient end;   an infrared spectroscopic analyzer positioned to analyze at least a portion of the sample;   a processor in communication with or incorporated into the spectroscopic analyzer; and   stored program instructions executable by the processor to obtain measurements of two or more properties of the sample, wherein the program instructions are configured to cause the fluid analyzer to:
 obtain a spectral characterization of the at least a portion of the sample, the spectral characterization incorporating one or more mid-infrared wavelengths; 
 analyze the spectral characterization to obtain a measurement of the level of a first analyte in at least a portion of the sample; and 
 analyze the same spectral characterization to obtain a measurement of the level of a second analyte in at least a portion of the sample when the first analyte and the second analyte have overlapping spectral features, such that the results of the spectral characterization are sensitive both the first analyte and the second analyte. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the spectral characterization includes wavelengths between about 5 μm and about 20 μm. 
     
     
         3 . The apparatus of  claim 1 , wherein the spectral characterization includes wavelengths between about 5.25 μm and about 12.0 μm. 
     
     
         4 . The apparatus of  claim 1 , wherein the at least a portion of the sample is whole blood. 
     
     
         5 . The apparatus of  claim 1 , wherein the at least a portion of the sample is blood plasma. 
     
     
         6 . The apparatus of  claim 1 , wherein the valve system comprises a first pump operable in the infusion mode but not in the sample draw mode, and a second pump operable in the sample draw mode but not in the infusion mode. 
     
     
         7 . A method of analyzing body fluid, the method comprising:
 drawing a sample of the bodily fluid of the patient through a fluid handling network configured to maintain fluid communication with a bodily fluid in a patient;   directing at least a portion of the sample to an infrared spectroscopic analyzer connected to the fluid handling network;   obtaining a spectral characterization from the at least a portion of the sample in the infrared spectroscopic analyzer, the spectral characterization including one or more mid-infrared wavelengths; and   analyzing the at least a portion of the sample in the infrared spectroscopic analyzer to obtain two or more analyte levels by:
 analyzing the spectral characterization to obtain an estimate of a level of a first analyte in the at least a portion of the sample; and 
 analyzing the same spectral characterization to obtain an estimate of a level of a second analyte in the at least a portion of the sample. 
   
     
     
         8 . The method of  claim 7 , wherein the at least a portion of the sample comprises whole blood, blood plasma, or blood serum. 
     
     
         9 . The method of  claim 7 , wherein the spectral characterization includes wavelengths between about 5 μm and about 20 μm. 
     
     
         10 . The apparatus of  claim 7 , wherein the spectral characterization includes wavelengths between about 5.25 μm and about 12.0 μm. 
     
     
         11 . The method of  claim 7 , wherein analyzing the at least a portion of the sample comprises:
 identifying one or more interferents to the estimate of the level of the first analyte, and   reducing errors in the estimate of the level of the first analyte.   
     
     
         12 . The method of  claim 11 , wherein analyzing the at least a portion of the sample comprises:
 identifying one or more interferents to the estimate of the level of the second analyte, and   reducing errors in the estimate of the level of the second analyte.   
     
     
         13 . An apparatus for analyzing the composition of bodily fluid, the apparatus comprising:
 a fluid handling network including a patient end configured to maintain fluid communication with a bodily fluid in a patient;   a valve system in operative engagement with the fluid handling network, the valve system having an infusion mode in which the valve system is operable to deliver infusion fluid to the patient through the patient end, and a sample draw mode in which the valve system is operable to draw a sample of the bodily fluid from the patient through the patient end;   a infrared spectroscopic analyzer positioned to analyze at least a portion of the sample;   a processor in communication with or incorporated into the infrared spectroscopic analyzer; and   stored program instructions executable by the processor to obtain measurements of the levels of two or more analytes in the at least a portion of the sample, wherein the program instructions are configured to cause the infrared spectroscopic analyzer to:
 obtain a spectral characterization from the at least a portion of the sample in the infrared spectroscopic analyzer, the spectral characterization including one or more mid-infrared wavelengths; 
 analyze the spectral characterization to obtain an estimate of a level of a first analyte in the at least a portion of the sample; and 
 analyze the same spectral characterization to obtain an estimate of a level of a second analyte in the at least a portion of the sample. 
   
     
     
         14 . The method of  claim 13 , wherein the at least a portion of the sample comprises whole blood, blood plasma, or blood serum. 
     
     
         15 . The method of  claim 13 , wherein the spectral characterization includes wavelengths between about 5 μm and about 20 μm. 
     
     
         16 . The apparatus of  claim 13 , wherein the spectral characterization includes wavelengths between about 5.25 μm and about 12.0 μm. 
     
     
         17 . The method of  claim 13 , wherein the program instructions are configured to cause the infrared spectroscopic analyzer to:
 identify one or more interferents to the estimate of the level of the first analyte, and   reduce errors in the estimate of the level of the first analyte.   
     
     
         18 . The method of  claim 11 , wherein the program instructions are configured to cause the infrared spectroscopic analyzer to:
 identify one or more interferents to the estimate of the level of the second analyte, and   reduce errors in the estimate of the level of the second analyte.