title: Comparison of the Diagnostic Accuracy of Three Rapid Tests for the Serodiagnosis of Hepatic Cystic Echinococcosis in Humans.
abstract: BACKGROUND
  The diagnosis of cystic echinococcosis (CE) is based primarily on imaging, in particular with ultrasound for abdominal CE, complemented by serology when imaging results are unclear. In rural endemic areas, where expertise in ultrasound may be scant and conventional serology techniques are unavailable due to lack of laboratory equipment, Rapid Diagnostic Tests (RDTs) are appealing.
  
  
  RESULTS
  We evaluated the diagnostic accuracy of 3 commercial RDTs for the diagnosis of hepatic CE. Sera from 59 patients with single hepatic CE cysts in well-defined ultrasound stages (gold standard) and 25 patients with non-parasitic cysts were analyzed by RDTs VIRapid HYDATIDOSIS (Vircell, Spain), Echinococcus DIGFA (Unibiotest, China), ADAMU-CE (ICST, Japan), and by RIDASCREEN Echinococcus IgG ELISA (R-Biopharm, Germany). Sensitivity, specificity and ROC curves were compared with McNemar and t-test. For VIRapid and DIGFA, correlation between semiquantitative results and ELISA OD values were evaluated by Spearman's coefficient. Reproducibility was assessed on 16 randomly selected sera with Cohen's Kappa coefficient. Sensitivity and Specificity of VIRapid (74%, 96%) and ADAMU-CE (57%, 100%) did not differ from ELISA (69%, 96%) while DIGFA (72%, 72%) did (p = 0.045). ADAMU-CE was significantly less sensitive in the diagnosis of active cysts (p = 0.019) while DIGFA was significantly less specific (p = 0.014) compared to ELISA. All tests were poorly sensitive in diagnosing inactive cysts (33.3% ELISA and ADAMU-CE, 42.8% DIGFA, 47.6% VIRapid). The reproducibility of all RDTs was good-very good. Band intensity of VIRapid and DIGFA correlated with ELISA OD values (r = 0.76 and r = 0.79 respectively, p<0.001).
  
  
  CONCLUSIONS
  RDTs may be useful in resource-poor settings to complement ultrasound diagnosis of CE in uncertain cases. VIRapid test appears to perform best among the examined kits, but all tests are poorly sensitive in the presence of inactive cysts, which may pose problems with accurate diagnosis.
authors.affiliation: Department of Clinical Surgical Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy.|WHO Collaborating Centre for the Clinical Management of Cystic Echinococcosis, Pavia, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Tamarozzi
authors.affiliation: Department of Clinical Surgical Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Covini
authors.affiliation: Department of Clinical Surgical Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy.|WHO Collaborating Centre for the Clinical Management of Cystic Echinococcosis, Pavia, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Mariconti
authors.affiliation: Department of Clinical Surgical Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy.|WHO Collaborating Centre for the Clinical Management of Cystic Echinococcosis, Pavia, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Narra
authors.affiliation: Clinical Epidemiology and Biometry Unit, San Matteo Hospital Foundation, Pavia, Italy.
authors.forename: Carmine
authors.initials: C
authors.lastname: Tinelli
authors.affiliation: Clinical Epidemiology and Biometry Unit, San Matteo Hospital Foundation, Pavia, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: De Silvestri
authors.affiliation: Clinical Epidemiology and Biometry Unit, San Matteo Hospital Foundation, Pavia, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Manzoni
authors.affiliation: Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanitá, Roma, Italy.
authors.forename: Adriano
authors.initials: A
authors.lastname: Casulli
authors.affiliation: Department of Parasitology, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ito
authors.affiliation: Medical Services and Diagnostic, Swiss Tropical and Public Health Institute, and University of Basel, Basel, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Neumayr
authors.affiliation: Department of Clinical Surgical Diagnostic and Paediatric Sciences, University of Pavia, Pavia, Italy.|WHO Collaborating Centre for the Clinical Management of Cystic Echinococcosis, Pavia, Italy.|Division of Tropical and Infectious Diseases, San Matteo Hospital Foundation, Pavia, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Brunetti
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D004444:Echinococcosis, Hepatic / Q000097:blood / Q000175:diagnosis* / Q000469:parasitology; D004446:Echinococcus / Q000276:immunology* / Q000302:isolation & purification; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012698:Serologic Tests / Q000379:methods*
chemical_list: D000909:Antibodies, Helminth