|
The results of two
commercially available C. trachomatis detection assays did
not agree when used to test urine samples from men.
A comparison
of two methods for detection of Chlamydia trachomatis in the
male urethra.
Opaneye AA, Bashford J, Ashton V.
J R Soc Health.
2002;122:58-60.
Summary:
Question
How do an enzyme immunoassay for the detection of C. trachomatis
antigen and a strand displacement amplification assay for the detection of
C. trachomatis DNA compare for screening urine samples from men for
C. trachomatis infection?
Design
This study describes a direct comparison of two commercially available
assays for the detection of C. trachomatis in urine samples from
men.
Participants
Sixty-one men between 17 and 57 years of age, attending a genitourinary
medicine department in the UK were tested. Twenty-two men had reported
symptoms (discharge, discomfort, or combination). Criteria for participant
selection were not stated.
Description of Tests and Diagnostic
Standard
Urethral samples were collected first, using a plastic loop and then a
swab, followed by collection of urine samples. The urine samples were
tested for C. trachomatis DNA with the BD Probe Tec strand
displacement amplification (SDA) assay. The assay is based on the
simultaneous amplification and detection of target DNA using primers and a
fluorescent probe. Each sample was also tested in a separate well for the
amplification of a reaction control to rule out sample inhibition. The
urethral swabs were tested for C. trachomatis antigen with the
Abbott IMX Select chlamydia assay. The assay is an enzyme immunoassay (EIA)
that uses microparticles to bind extracted C. trachomatis LPS,
which is detected by antibodies and a fluorescent substrate. Positive
samples were confirmed by testing with either a blocking reaction or an
immunofluorescent antibody test.
Main Outcome Measures
The EIA and SDA results for each specimen were compared.
Main Results
Seven patients tested positive for C. trachomatis by either assay:
2 by EIA only, 3 by SDA only, and 2 by both assays . The characteristics
of these 7 patients are shown in the table
| Characteristics
of patients positive for Chlamydia trachomatis by SDA and/or
EIA |
| Symptoms |
EIA
(Abbott IMX) |
SDA (BD
Probe Tec) |
| + |
+ |
+ |
| + |
+ |
+ |
| neg |
neg |
+ |
| + |
neg |
+ |
| + |
neg |
+ |
| neg |
+ |
neg |
| neg |
+ |
neg |
Authors' Conclusions
No conclusion can be made as to which of
these two assays performed better for screening these men for C.
trachomatis infection.
Source of funding: None given
For correspondence: Abayomi Opaneye,
Department of Genitourinary Medicine, Middlebrough General Hospital,
Ayresome Green Lane, Middlesbrough, Cleveland TS5 5AZ, England.
expert
review
|
.gif){kind=small}