Diagnosis of Giardia lamblia infections by detection of parasite-specific antigens.

Journal Article (Journal Article)

Antigen detection methods may facilitate diagnosis of Giardia lamblia in stool specimens. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and immunoblotting, G. lamblia cysts and trophozoites share several antigens, especially in the 65-kilodalton and 30- to 34-kilodalton regions. By using blind methods, we compared results obtained by counterimmunoelectrophoresis using cyst-immune rabbit serum and by enzyme-linked immunosorbent assay (ELISA) using trophozoite-immune rabbit serum with results obtained by microscopic examination of a preserved, concentrated, and permanently stained stool specimen. Results were similar when these three methods were used to examine 118 stool specimens from clinical microbiology laboratories (53 specimens with G. lamblia) and specimens from 239 day-care-center toddlers (39 specimens with G. lamblia). Compared with microscopy, we found, for counterimmunoelectrophoresis and ELISA, respectively: sensitivity, 88 versus 94%; specificity, 97 versus 95%; positive predictive value, 86 versus 76%; negative predictive value, 98 versus 97%; and concordance, 89%. The false-positive rate by ELISA was 24% (10 of 42) in day-care-center toddlers but only 3% (1 of 32) in healthy adults (P less than 0.04) as corroborated by microscopy. This discrepancy suggests that the ELISA may be more sensitive than microscopy, which is considered the reference standard, and that results may be dependent, in part, on the epidemiology of the infection in the study subjects.

Full Text

Duke Authors

Cited Authors

  • Janoff, EN; Craft, JC; Pickering, LK; Novotny, T; Blaser, MJ; Knisley, CV; Reller, LB

Published Date

  • March 1989

Published In

Volume / Issue

  • 27 / 3

Start / End Page

  • 431 - 435

PubMed ID

  • 2715318

Pubmed Central ID

  • PMC267335

International Standard Serial Number (ISSN)

  • 0095-1137

Digital Object Identifier (DOI)

  • 10.1128/jcm.27.3.431-435.1989


  • eng

Conference Location

  • United States