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Local laboratory
testing and physician assessment were not accurate for diagnosis of
STDs in Hefei, China.
Do STD clinics correctly diagnose
STDs? An assessment of STD management in Hefei, China.
Liu H, Detels R, Yin Y, Li X, Visscher B.
International
Journal of STD and AIDS 2003;14:665-671.
Summary:
Question
What is the accuracy of local laboratory testing and of the diagnosis
provided by a physician in STD clinics in Hefei, China?
Design
This study describes a blinded comparison of local laboratory test results
and of physician diagnoses with the results of tests performed at the
China National Center for STD Control and Prevention for the detection of
sexually transmitted diseases among men attending STD clinics in Hefei,
China.
Participants
Four hundred six consecutive men who complained of urethral discharge or
dysuria (n= 350), or genital ulcers (n=55), or both (n=1), who were
attending for the first time for their current symptoms, were tested.
Among the 406, 23% had had a different STD episode in the previous 12
months, 68% were married, 59% had a high school or better education, and
30% were private businessmen. The men attended one of four urban STD
clinics in Hefei. Two clinics were run by the local health department and
two were private clinics. All four clinics received at least one new
patient per day and were the only clinics in their districts.
Description of Tests and Diagnostic
Standard
Local laboratories used their routine methods and procedures for STD
testing. Review of records from one month before the study began indicated
that the local laboratories and physicians did not change their usual
procedures during the study period. Urethral swabs from each man
complaining of urethral discharge or dysuria were tested for N.
gonorrhoeae by Gram stain and/or culture, and for C. trachomatis
by culture, direct fluorescent antibody, or enzyme immunoassay. Blood
samples taken from each man complaining of genital ulcers were tested for
syphilis by the rapid plasma reagin (RPR) test and/or the T. pallidum
hemagglutination test. No tests were performed for HSV.
Physicians made diagnoses based on both
results from the local laboratory and their experience. A presumptive
diagnosis was based on a physical examination followed by the final
diagnosis made according to the results of the laboratory tests. Diagnosis
of HSV was made solely based on the patient's clinical signs and symptoms.
First catch urine samples were collected
from each man complaining of urethral discharge or dysuria and transported
frozen to the China National Center for STD Control and Prevention for N.
gonorrhoeae and C. trachomatis testing using PCR (Amplicor
CT/NG, Roche, Branchburg, NJ). Swabs of lesion material were collected
from each man complaining of genital ulcers, transported frozen, and
tested for HSV by PCR. Serum aliquots were tested for syphilis by RPR (Urumoqi,
China) and positive specimens confirmed using a T. pallidum
antibody particle agglutination test (SERODIA, Fujirebio Inc., Tokyo,
Japan).
Main Outcome Measures
Results from the STD clinics (laboratory testing and physician diagnoses)
and the National Center were compared using the testing results from the
National Center as the gold standard. The sensitivity, specificity,
positive predictive value (PPV), and negative predictive value (NPV) of
the local laboratory tests and the physicians' diagnoses were calculated.
Main Results
Among the 350 specimens from men with urethral discharge or dysuria, 240,
310, and 347 specimens tested positive for N. gonorrhoeae, C.
trachomatis, or both at the National Center, at the local laboratory,
or by physician diagnosis, respectively. Among the 55 specimens from men
with genital ulcers, 28 and 52 were positive for either syphilis or HSV by
testing at the National Center or by physician diagnosis, respectively.
The performances of the local laboratory tests and of physicians'
diagnoses compared to testing at the National Center are shown in the
table. The sensitivity and specificity of local laboratory testing was
fairly high for detection of infection with N. gonorrhoeae but very
low for C. trachomatis. The physicians had a high sensitivity for
syphilis diagnosis and a marginal sensitivity for HSV, but the PPVs were
low for both diagnoses. Among men providing samples with negative tests by
the local laboratories, 16 of 141 were diagnosed by physicians as having
gonorrhea, 70 of 176 were diagnosed as having chlamydia, and 6 of 33 were
diagnosed as having syphilis. Among 171 men with a positive local
laboratory test for chlamydia, 29 were diagnosed as having gonorrhea, HSV,
or syphilis.
Authors' Conclusions
The current management of STDs in Hefei was
inadequate. The quality of local laboratory testing was not high and
physicians often misdiagnosed STDs. The syndromic approach, especially for
C. trachomatis infections, mixed infections involving C.
trachomatis, and genital ulcer disease, should be considered in areas
that have inadequate laboratory and physician resources.
Source of funding:
The Fogarty International Center
For correspondence:
Roger Detels, Department of Epidemiology, School of Public Health,
University of California, Los Angeles, Box 951772, Los Angeles, CA
09995-1772. E-mail address: detels@ucla.edu
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