[Validity of the Gram and Lendrum stains in conjunctival smears for the identification of Chlamydia trachomatis].
With the objective of finding reliable, valid, and economic diagnostic tests to identify Chlamydia trachomatis in conjunctival smears, the sensitivity, specificity, and positive and negative predictive values of Lendrum and Giemsa stains were evaluated using direct immunofluorescence as the gold standard. In addition, inter- and intraobserver reproducibility were estimated through the use of two independent observers, who were blinded to the results during their readings. The prevalence of ocular chlamydiosis in the study area was around 50%. In all, 103 persons (206 eyes) were studied. Three smears from each eye were taken for each subject. The kappa statistic was used to estimate the reproducibility of the stains. Interobserver reproducibility was null, and intraobserver reproducibility ranged between 0.35 and 0.79. The sensitivity of the Giemsa stain was a bit higher than that of the Lendrum stain (28% and 22%, respectively), and the specificity was similar (82% and 85%, respectively). Based on these results, the ability of both stains to detect positive cases was judged to be low, as was their reliability. The Lendrum and Giemsa stains are not adequate tests for the diagnosis of ocular chlamydiosis. For this purpose the use of direct immunofluorescence is recommended.
de Ramírez
I
I
Hospital de Ojos y Oídos Dr. Rodolfo Robles V, Guatemala.
Mejía
M
M
García de la Riva
J C
JC
Hermes
F
F
Grazioso
C F
CF
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001399:Azure Stains; D002648:Child; D002675:Child, Preschool; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D003235:Conjunctivitis, Inclusion / Q000175:diagnosis / Q000382:microbiology*; D003951:Diagnostic Errors; D005455:Fluorescent Antibody Technique; D006801:Humans; D002479:Inclusion Bodies / Q000648:ultrastructure; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013194:Staining and Labeling
D001399:Azure Stains