Accuracy and clinical correlates of two different methods for chromogranin A assay in neuroendocrine tumors

L. Ferrari, E. Seregni, G. Lucignani, E. Bajetta, A. Martinetti, G. Aliberti, F. Pallotti, G. Procopio, S. Della Torre, R. Luksch, Emilio Bombardieri

Research output: Contribution to journalArticle

Abstract

Measurement of chromogranin A (CgA) plays a major role in the management of neuroendocrine tumors (NET); however, reliable assaying of CgA is made difficult by the rapid hydrolysis following its release into the bloodstream. This study was aimed at the assessment of two assays for CgA in NET patients. CgA was measured in 93 patients by means of an enzyme-linked immunosorbent assay (ELISA) and an immunoradiometric assay (IRMA). The specificity and sensitivity of CgA were evaluated in relation to tumor histology. The clinical accuracy of the two assays was evaluated by receiver-operating characteristic (ROC) curve analysis. Regression analysis demonstrated different immunoreactivity for CgA of the antibodies used in the two kits (r=0.61). The two assays had different accuracy also in classifying patients according to their clinical condition (91% vs 64% specificity and 79% vs 79% sensitivity for the ELISA and IRMA assay, respectively) and tumor histology (81% vs 85% sensitivity for the ELISA and IRMA assays, respectively, in carcinoids; 92% vs 67% sensitivity for the ELISA and IRMA assays, respectively, in pancreatic islet cell tumors). The different clinical accuracy of the two assays was confirmed by the ROC analysis (AUC=0.90 vs AUC=0.87 for the ELISA and IRMA assays, respectively). In conclusion, because of the poor standardization of the commercially available measurement tools the clinical accuracy of CgA measurement depends on the assay used. This makes it difficult to compare CgA values measured with different kits and affects the clinical accuracy of the different assays for CgA.

Original languageEnglish
Pages (from-to)295-304
Number of pages10
JournalInternational Journal of Biological Markers
Volume19
Issue number4
Publication statusPublished - Oct 2004

Keywords

  • Carcinoid
  • Chromogranin A
  • Enzyme-linked immunosorbent assay
  • Immunoradiometric assay
  • Neuroendocrine tumors
  • Pancreatic islet cell tumor
  • Tumor markers

ASJC Scopus subject areas

  • Immunology
  • Biochemistry

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