In a diagnostic test study the validity of three serodiagnostic test was compared in patients with liver echinococcosis.
OBJECTIVE
To determine the efficacy of immunoprecipitation (DD5), enzyme immunoanalysis (ELISA-IgG), and immunoelectrotransference or Western blot (WB) in patients with liver echinococcosis (LE) used separately, in parallel and in series.


METHODS
Diagnostic test study. DD5, ELISA-IgG, and WB were applied in 75 patients with LE and 75 with cholelithiasis. Surgery was considered a reference standard. The sample size was calculated assuming a 99% confidence interval (99% CI), expected sensitivity (S) of 90% and a worst result of 80%; expected specificity (SP) of 95% and a worst result of 85%. S, SP, and predictive values (PPV and NPV) were calculated.


RESULTS
The best S was verified with ELISA-IgG and WB (82.7%) and the best SP with DD5 (94.7%). DD5 presented a better PPV (92.9%) and WB a better NPV (83.5%). When applying the tests in parallel, the best S was obtained from the combination of DD5 and WB (82.7%); and the best SP, PPV and NPV with ELISA-IgG and WB (88.0%, 87.3%, and 83.5%, respectively).


CONCLUSIONS
DD5 appears as the most specific test and as having greater PPV; ELISA-IgG and WB are more sensitive. The combined use of these tests does not improve diagnosis validity.
Manterola
Carlos
C
Department of Surgery, Hospital Regional de Temuco, Faculty of Medicine, Universidad de La Frontera, Casilla 54-D, Temuco, Chile. cmantero@ufro.cl
Cuadra
Alvaro
A
Muñoz
Sergio
S
Sanhueza
Antonio
A
Bustos
Luis
L
Vial
Manuel
M
Fonseca
Flery
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D001652:Bile Ducts / Q000473:pathology; D015153:Blotting, Western / Q000379:methods; D004444:Echinococcosis, Hepatic / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D047468:Immunoprecipitation / Q000379:methods; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D012698:Serologic Tests
D007074:Immunoglobulin G