NGAL for Diagnosis of Renal Conditions

Abstract

Use of serum neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker, alone or in conjunction with creatinine to aid in the diagnosis of renal conditions such as acute tubular necrosis and acute renal failure, and a method and a kit for assigning a diagnosis of acute tubular necrosis or acute renal failure to a subject based on the correlation between the levels of NGAL and optionally creatinine in a sample obtained from a subject when compared to a sample obtained from a normal subject not experiencing acute tubular necrosis or acute renal failure.

We claim: 
     
         1 . A method of assigning a diagnosis of acute tubular necrosis to a subject, comprising:
 a) performing an immunoassay that detects neutrophil gelatinase-associated lipocalin (NGAL) on a sample of blood, serum or plasma obtained from a subject at a time preceding a rise in serum creatinine, wherein the immunoassay comprises (i) contacting the sample with a medium comprising an antibody that detects NGAL, and (ii) detecting binding to the antibody, thereby determining the level of NGAL in the sample;   b) comparing the level of NGAL in the sample obtained from the subject with a level of NGAL in a sample from a normal subject; and   c) assigning a diagnosis of acute tubular necrosis (ATN) when the level of NGAL in the sample obtained from the subject is greater than the level of NGAL in the sample from the normal subject, at a time preceding a diagnosis of ATN based on a rise in serum creatinine.   
     
     
         2 . The method of  claim 1  wherein the level of NGAL in the sample obtained from the subject is at least about 7 fold greater than the level of NGAL in the sample from the normal subject. 
     
     
         3 . The method of  claim 1  wherein the level of NGAL in the sample from the normal subject is about 20 ng/mL. 
     
     
         4 . A method of diagnosing whether a subject is experiencing acute renal failure or chronic renal failure, comprising;
 a) measuring the level of NGAL in a sample obtained from the subject;   b) measuring the level of creatinine in a sample obtained from the subject;   c) correlating the level of NGAL with the level of creatinine, and assigning a diagnosis of acute renal failure or chronic renal failure based on said correlation.   
     
     
         5 . The method of  claim 4  wherein when there is a high correlation between the measured level of NGAL and creatinine, assigning a diagnosis of acute renal failure to said subject. 
     
     
         6 . The method of  claim 4  wherein when there is no correlation between the measured level of NGAL and creatinine, assigning a diagnosis of chronic renal failure to said subject. 
     
     
         7 . The method of  claim 4  wherein the level of NGAL is measured in a sample of serum obtained from said subject. 
     
     
         8 . The method of  claim 4  wherein the level of creatinine is measured in a sample of serum obtained from said subject. 
     
     
         9 . The method of  claim 4  wherein the level of NGAL is measured in a sample of plasma obtained from said subject. 
     
     
         10 . The method of  claim 4  wherein the level of NGAL is measured in a sample of blood obtained from said subject. 
     
     
         11 . A kit for the diagnosis of acute renal failure or chronic renal failure in a subject, comprising:
 a) a monoclonal antibody that recognises human NGAL;   b) a tube for collecting a blood sample containing either citrate, EDTA or heparin;   c) instructions for obtaining an assay result and performing a correlation of assay data to determine whether a subject has acute renal failure or chronic renal failure; wherein said instructions further indicate that a high degree of correlation between a NGAL level and creatinine level is indicative of acute renal failure; and wherein when there is no correlation between a NGAL level and creatinine level, said instructions indicate chronic renal failure is present.   
     
     
         12 . The method of  claim 1  wherein the subject is human. 
     
     
         13 . The method of  claim 2  wherein the subject is human. 
     
     
         14 . The method of  claim 3  wherein the subject is human. 
     
     
         15 . The method of  claim 1 , further including the step d) of using the diagnosis in step c) to inform a decision on administering a treatment for acute tubular necrosis to the subject having the acute tubular necrosis. 
     
     
         16 . The method of  claim 1 , further including the step d) of using the diagnosis in step c) to inform a decision on administering a treatment for acute tubular necrosis to the subject, that precedes a diagnosis of ATN based on a rise in serum creatinine.