title: A comparison of three chromogranin A assays in patients with neuroendocrine tumours.
abstract: OBJECTIVE
  Chromogranin A (CgA) is the most important general tumour marker used in the diagnosis and follow-up of patients with neuroendocrine tumours (NET). Chromogranin A assays may have different sensitivities, which is of importance for the clinical diagnosis and handling of NET patients. The aim of this study was to compare the clinical sensitivities of three different CgA assays in NET patients.
  
  
  METHODS
  We measured CgA level in 42 NET patients (male/female: 23/19, median age: 63 years, range 29-85 years). Twenty-five patients had liver metastases, eight had local disease, and nine were disease free after surgery. We studied an in-house RIA: RH RIA assay (Rigshospitalet, Copenhagen, Denmark); NEOLISATM (Euro Diagnostica, Malmö, Sweden) and EURIA CgA RIA (Euro Diagnostica, Malmö, Sweden).
  
  
  RESULTS
  The RH RIA assay showed a clinical sensitivity of 97%, while the NEOLISA and EURIA assays both showed similar clinical sensitivities of 79%. Patients with liver metastases had significantly higher CgA levels compared to disease free patients by all three assays (P<0.001), but only the RH RIA assay was able to discriminate between patients with liver metastases and with regional disease (P<0.01).
  
  
  CONCLUSIONS
  Chromogranin A measurements are significantly assay-dependent and caution should be applied in the interpretation of CgA measurement for assessment of NET status. The in-house RH RIA assay was better at predicting NET status than the NEOLISA and EURIA assays.
authors.affiliation: Department of Medicine V (Hepatology and Gastroenterology), Aarhus University Hospital, Aarhus, Denmark. lisebrehmhoej@hotmail.com.
authors.forename: Lise
authors.initials: L
authors.lastname: Brehm Hoej
authors.affiliation: Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Tina
authors.initials: T
authors.lastname: Parkner
authors.affiliation: Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Cindy
authors.initials: C
authors.lastname: Soendersoe Knudsen
authors.affiliation: Department of Medicine V (Hepatology and Gastroenterology), Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Henning
authors.initials: H
authors.lastname: Grønbaek
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D053379:Chromogranin A / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000737:chemistry* / Q000473:pathology / Q000601:surgery; D011237:Predictive Value of Tests; D011379:Prognosis; D011863:Radioimmunoassay; D015203:Reproducibility of Results
chemical_list: D014408:Biomarkers, Tumor; C506150:CHGA protein, human; D053379:Chromogranin A