Immunoassay method for pro-gastrin-releasing peptide

Abstract

To provide a more convenient and more accurate method of assaying ProGRP by improving the stability of ProGRP which is known to be unstable in a biological sample. By using a blood sample in a condition in which a blood coagulation factor is not activated is used as a sample, the degradation of ProGRP is suppressed, whereby it is possible to store a sample for a long period of time and to improve the accuracy of an assay.

1 . A method of assaying ProGRP in a blood sample comprising the steps of:
 a)contacting said blood sample with an antibody against ProGRP for a time and under conditions sufficient for formation of antibody/ProGRP complexes, wherein said blood sample comprises one or more unactivated blood coagulation factors; and   b) detecting presence of said antibody/ProGRP complexes, presence of said complexes indicating presence of ProGRP in said blood sample.   
   
   
       2 . The method of assaying ProGRP according to  claim 1 , wherein a said blood sample comprises unactivated thrombin. 
   
   
       3 . The method of assaying ProGRP according to  claim 1  or  claim 2 , wherein plasma is used as the sample. 
   
   
       4 . (canceled) 
   
   
       5 . The method of assaying ProGRP according to  claim 1 , wherein the region covering amino acids 31-98 of ProGRP is assayed. 
   
   
       6 . The method of assaying ProGRP according to  claim 1 , wherein said sample is stored for more than 6 hours in refrigeration storage after collection. 
   
   
       7 . The method of assaying ProGRP according to  claim 6 , wherein said sample is stored for more than 24 hours in refrigeration storage after collection. 
   
   
       8 . The method of assaying ProGRP according to  claim 1 , wherein said sample is left or stored at room temperature after collection. 
   
   
       9 . A method of improving the in vivo stability of a serum sample containing ProGRP comprising the step of adding to a serum sample containing ProGRP obtained from a subject a stabilizing amount of at least one serum protease inhibitor. 
   
   
       10 . The method of  claim 9 , wherein the serine protease inhibitor is phenylmethylsulfonyl fluoride. 
   
   
       11 . The method of  claim 9 , wherein the at least one serum protease inhibitor is added to a sample collection vessel after serum is added to the sample collection vessel. 
   
   
       12 . A ProGRP-stabilizing composition, wherein said composition comprises at least one serine protease inhibitor. 
   
   
       13 . A sample collection vessel containing the composition of  claim 12 . 
   
   
       14 . A kit for stabilizing ProGRP in a serum sample, the kit comprising:
 (a) at least one serum protease inhibitor; and   (b) instructions for using the kit.   
   
   
       15 . The kit of  claim 14  wherein the at least one serum protease inhibitor is phenylmethylsulfonyl fluoride.