Method and Device for Combined Detection of Viral and Bacterial Infections

Abstract

A lateral flow assay is capable of detecting and differentiating viral and bacterial infections. A combined point of care diagnostic device tests markers for viral infection and markers for bacterial infection, to effectively assist in the rapid differentiation of viral and bacterial infections. In some preferred embodiments, bimodal methods and devices determine if an infection is bacterial and/or viral. A dual use two strip sample analysis device includes a first lateral flow chromatographic test strip to detect MxA and a low level of C-reactive protein and a second lateral flow chromatographic test strip to detect high levels of C-reactive protein. In some preferred embodiments, the sample is a fingerstick blood sample.

What is claimed is: 
     
         1 . A method for determining if an infection is bacterial and/or viral, comprising the steps of:
 a) collecting a sample;   b) transferring the sample to a sample analysis device comprising:
 i) a first lateral flow chromatographic test strip comprising:
 a first reagent zone comprising at least one first reagent specific to a low level of C-reactive protein such that, when the sample contacts the first reagent, a first labeled complex forms if the low level of C-reactive protein is present in the sample; 
 a second reagent zone comprising at least one second reagent specific to MxA such that, when the sample contacts the second reagent, a second labeled complex forms if MxA is present in the sample; and 
 a detection zone comprising a first binding partner which binds to the first labeled complex; and a second binding partner which binds to the second labeled complex; and 
 
 ii) a second lateral flow chromatographic test strip parallel in a lateral flow direction to the first lateral flow chromatographic test strip, comprising:
 at least one third reagent zone comprising: 
 at least one third reagent specific to a high level of C-reactive protein, wherein the third reagent only detects a level of C-reactive protein that is higher than the level of C-reactive protein detected by the first reagent, such that, when the sample contacts the third reagent, a third labeled complex forms if the high level of C-reactive protein is present in the sample; and 
 a detection zone comprising a third binding partner which binds to the third labeled complex; and 
 
 c) analyzing the sample for a presence of the low level of C-reactive protein, MxA, and the high level of C-reactive protein. 
   
     
     
         2 . The method of  claim 1 , wherein a threshold concentration to obtain a positive result for the low level of C-reactive protein in the detection zone of the first lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 6-15 mg/L of C-reactive protein. 
     
     
         3 . The method of  claim 1 , wherein the threshold concentration to obtain a positive result for the low level of C-reactive protein in the detection zone of the first lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 10 mg/L of C-reactive protein. 
     
     
         4 . The method of  claim 1 , wherein a threshold concentration to obtain a positive result for the high level of C-reactive protein in the detection zone of the second lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 60-100 mg/L. 
     
     
         5 . The method of  claim 1 , wherein a threshold concentration to obtain a positive result for the high level of C-reactive protein in the detection zone of the second lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 80 mg/L. 
     
     
         6 . The method of  claim 1 , wherein a threshold concentration to obtain a positive result for MxA in the detection zone of the first lateral flow chromatographic test strip is equal to or greater than approximately 40 ng/ml. 
     
     
         7 . The method of  claim 1 , wherein a threshold concentration to obtain a positive result for MxA in the detection zone of the first lateral flow chromatographic test strip is equal to or greater than approximately 15-250 ng/ml. 
     
     
         8 . The method of  claim 1 , wherein a first threshold concentration to obtain a positive result for the low level of C-reactive protein in the detection zone of the first lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 6-15 mg/L of C-reactive protein, a second threshold concentration to obtain a positive result for the high level of C-reactive protein in the detection zone of the second lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 60-100 mg/L, and a third threshold concentration to obtain a positive result for MxA in the detection zone of the first lateral flow chromatographic test strip is equal to or greater than approximately 15-250 ng/ml. 
     
     
         9 . The method of  claim 1 , wherein a first threshold concentration to obtain a positive result for the low level of C-reactive protein in the detection zone of the first lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 10 mg/L of C-reactive protein, a second threshold concentration to obtain a positive result for the high level of C-reactive protein in the detection zone of the second lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 80 mg/L, and a third threshold concentration to obtain a positive result for MxA in the detection zone of the first lateral flow chromatographic test strip is equal to or greater than approximately 40 ng/ml. 
     
     
         10 . The method of  claim 1 , wherein step c) comprises the substeps of:
 i) eluting the sample on the sample analysis device; and   ii) visually determining a result from the detection zone.   
     
     
         11 . The method of  claim 1 , wherein the presence of MxA is indicated by a first test line located in the detection zone of the first lateral flow chromatographic test strip and the presence of the low level of CRP is indicated by a second test line located in the detection zone of the first lateral flow chromatographic test strip. 
     
     
         12 . The method of  claim 11 , wherein the first test line displays a first color when positive and the second test line displays a second color different from the first color when positive. 
     
     
         13 . The method of  claim 12 , wherein both the first test line and the second test line are located in the same space on the sample analysis device such that a third color is formed when both the first test line and the second test line are positive. 
     
     
         14 . The method of  claim 11 , wherein the first test line is spatially separate from the second test line on the first lateral flow chromatographic test strip. 
     
     
         15 . The method of  claim 1 , wherein the sample is a blood sample. 
     
     
         16 . The method of  claim 1 , wherein the sample contains leukocytes. 
     
     
         17 . A device for the detection of a bacterial and/or viral marker in a sample, comprising:
 a) a first lateral flow chromatographic test strip comprising:
 a first reagent zone comprising at least one first reagent specific to a low level of C-reactive protein such that, when the sample contacts the first reagent, a first labeled complex forms if the low level of C-reactive protein is present in the sample; 
 a second reagent zone comprising at least one second reagent specific to MxA such that, when the sample contacts the second reagent, a second labeled complex forms if MxA is present in the sample; and 
 a first detection zone comprising a first binding partner which binds to the first labeled complex; and a second binding partner which binds to the second labeled complex; and 
   b) a second lateral flow chromatographic test strip parallel in a lateral flow direction to the first lateral flow chromatographic test strip, comprising:
 at least one third reagent zone comprising at least one third reagent specific to a high level of C-reactive protein, wherein the third reagent only detects a level of C-reactive protein that is higher than the level of C-reactive protein detected by the first reagent, such that, when the sample contacts the third reagent, a third labeled complex forms if the high level of C-reactive protein is present in the sample; and 
 a second detection zone comprising a third binding partner which binds to the third labeled complex. 
   
     
     
         18 . The device of  claim 17 , wherein a threshold concentration to obtain a positive result for the low level of C-reactive protein in the first detection zone of the first lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 6-15 mg/L of C-reactive protein. 
     
     
         19 . The device of  claim 17 , wherein the threshold concentration to obtain a positive result for the low level of C-reactive protein in the first detection zone of the first lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 10 mg/L of C-reactive protein. 
     
     
         20 . The device of  claim 17 , wherein a threshold concentration to obtain a positive result for the high level of C-reactive protein in the second detection zone of the second lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 60-100 mg/L. 
     
     
         21 . The device of  claim 17 , wherein a threshold concentration to obtain a positive result for the high level of C-reactive protein in the second detection zone of the second lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 80 mg/L. 
     
     
         22 . The device of  claim 17 , wherein a threshold concentration to obtain a positive result for MxA in the first detection zone of the first lateral flow chromatographic test strip is equal to or greater than approximately 40 ng/ml. 
     
     
         23 . The device of  claim 17 , wherein a threshold concentration to obtain a positive result for MxA in the first detection zone of the first lateral flow chromatographic test strip is equal to or greater than approximately 15-250 ng/ml. 
     
     
         24 . The device of  claim 17 , wherein a first threshold concentration to obtain a positive result for the low level of C-reactive protein in the first detection zone of the first lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 6-15 mg/L of C-reactive protein, a second threshold concentration to obtain a positive result for the high level of C-reactive protein in the second detection zone of the second lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 60-100 mg/L, and a third threshold concentration to obtain a positive result for MxA in the first detection zone of the first lateral flow chromatographic test strip is equal to or greater than approximately 15-250 ng/ml. 
     
     
         25 . The device of  claim 17 , wherein a first threshold concentration to obtain a positive result for the low level of C-reactive protein in the first detection zone of the first lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 10 mg/L of C-reactive protein, a second threshold concentration to obtain a positive result for the high level of C-reactive protein in the second detection zone of the second lateral flow chromatographic test strip is equal to or greater than a serum equivalent of approximately 80 mg/L, and a third threshold concentration to obtain a positive result for MxA in the first detection zone of the first lateral flow chromatographic test strip is equal to or greater than approximately 40 ng/ml. 
     
     
         26 . The device of  claim 17 , wherein the first detection zone of the first lateral flow chromatographic test strip comprises a first test line to detect a positive result for MxA in the sample and a second test line to detect a positive result for the low level of CRP in the sample. 
     
     
         27 . The device of  claim 26 , wherein the first test line displays a first color when positive and the second test line displays a second color different from the first color when positive. 
     
     
         28 . The device of  claim 27 , wherein both the first test line and the second test line are located in the same space on the first lateral flow chromatographic test strip such that a third color is formed when both the first test line and the second test line are positive. 
     
     
         29 . The device of  claim 26 , wherein the first test line is spatially separate from the second test line on the first lateral flow chromatographic test strip. 
     
     
         30 . The device of  claim 17 , wherein the first detection zone and the second detection zone each comprise a control line that is visible to the naked eye when the device is working. 
     
     
         31 . The device of  claim 17 , wherein the first lateral flow chromatographic test strip further comprises a first sample application zone upstream of the first reagent zone, the second reagent zone, and the first detection zone, and the first detection zone is downstream of the first reagent zone and the second reagent zone. 
     
     
         32 . The device of  claim 17 , wherein the second lateral flow chromatographic test strip further comprises a second sample application zone upstream of the third reagent zone, and the second detection zone, and the second detection zone is downstream of the third reagent zone. 
     
     
         33 . The device of  claim 17 , wherein the first lateral flow chromatographic test strip further comprises a lysis zone comprising at least one lysis agent, wherein the lysis agent contacts the sample on the first lateral flow chromatographic test strip. 
     
     
         34 . The device of  claim 17 , wherein the second lateral flow chromatographic test strip further comprises a lysis zone comprising at least one lysis agent, wherein the lysis agent contacts the sample on the second lateral flow chromatographic test strip. 
     
     
         35 . The device of  claim 17 , wherein the first lateral flow chromatographic test strip further comprises a first sample application zone downstream of the first reagent zone and the second reagent zone, and upstream the first detection zone. 
     
     
         36 . The device of  claim 17 , wherein the second lateral flow chromatographic test strip further comprises a second sample application zone downstream of the third reagent zone and upstream of the second detection zone. 
     
     
         37 . The device of  claim 17 , wherein the sample is a blood sample. 
     
     
         38 . The device of  claim 17 , wherein the sample contains leukocytes. 
     
     
         39 . A method to simultaneously detect at least one extracellular analyte and at least one intracellular analyte, comprising the steps of:
 a) collecting a sample;   b) transferring the sample to a sample analysis device;   c) lysing the sample; and   d) simultaneously detecting the extracellular analyte and the intracellular analyte on the sample analysis device.   
     
     
         40 . The method of  claim 39 , wherein the extracellular analyte is C-reactive protein and the intracellular analyte is MxA protein. 
     
     
         41 . The method of  claim 39 , wherein the sample is a blood sample. 
     
     
         42 . A method of detecting MxA protein and C-reactive protein in a sample, comprising the steps of:
 a) adding the sample to a mixture of an antibody to MxA protein conjugated to a first label and an antibody to C-reactive protein conjugated to a second label different from the first label;   b) detecting a presence of MxA protein by determining whether the antibody to MxA protein has agglutinated; and   c) detecting a presence of C-reactive protein by determining whether the antibody to C-reactive protein has agglutinated.   
     
     
         43 . The method of  claim 42 , further comprising, before step a), the steps of:
 d) conjugating the antibody to MxA protein to the first label;   e) conjugating the antibody to C-reactive protein to the second label.