STUDIES ON THE DETECTION KIT FOR THE COLORECTAL CARCINOMA ASSOCIATED LARGE EXTERNAL ANTIGEN
Abstract
Objective: To investigate the detecting method and diagnostic value of the tumor marker colorectal carcinoma associated large external antigen (LEA) for colorectal carcinoma.
Methods: Monoclonal antibody ND-1, which can recognize LEA, was labeled with biotin aminocaproylhydrazide (BACH) and horseradish peroxidase (HRP) respectively. One step sandwich ELISA Kit for detecting LEA in serum was developed by the biotinylated antibody and enzyme conjugation. The validity and reliability of the kit were evaluated by sera selected from clinic.
Results: the OD405 of healthy group was 0.056±0.038, and that of patients was 0.553±0.441. The difference between the two groups was significant (P<0.01). The cutoff value, which was 0.248, was determined by analysis of ROC. The diagnosis sensitivity, specificity and validity of the kit were 89.29%, 87.5%, 88.54% respectively. The ROC value was 0.95. The intra-CV was less than 5%, and the internal-CV was less than 10%. There was no significant difference between the results obtained by the kit and those obtained by pathological diagnosis (P<0.01). The expression of LEA was associated with the differentiated degree of colorectal carcinoma and had no relation to the Dukes' phase of the disease.
Conclusion: LEA is practically useful tumor marker for the diagnosis of colorectal carcinoma. The kit developed can be used for the qualitative diagnosis for the disease.
Methods: Monoclonal antibody ND-1, which can recognize LEA, was labeled with biotin aminocaproylhydrazide (BACH) and horseradish peroxidase (HRP) respectively. One step sandwich ELISA Kit for detecting LEA in serum was developed by the biotinylated antibody and enzyme conjugation. The validity and reliability of the kit were evaluated by sera selected from clinic.
Results: the OD405 of healthy group was 0.056±0.038, and that of patients was 0.553±0.441. The difference between the two groups was significant (P<0.01). The cutoff value, which was 0.248, was determined by analysis of ROC. The diagnosis sensitivity, specificity and validity of the kit were 89.29%, 87.5%, 88.54% respectively. The ROC value was 0.95. The intra-CV was less than 5%, and the internal-CV was less than 10%. There was no significant difference between the results obtained by the kit and those obtained by pathological diagnosis (P<0.01). The expression of LEA was associated with the differentiated degree of colorectal carcinoma and had no relation to the Dukes' phase of the disease.
Conclusion: LEA is practically useful tumor marker for the diagnosis of colorectal carcinoma. The kit developed can be used for the qualitative diagnosis for the disease.