2002 Laboratory Guidelines

Screening Tests To Detect Chlamydia trachomatis and Neisseria gonorrhoeae Infections - 2002

Appendix A

Indications for Chlamydia trachomatis Testing and Test Selection by Specimen Type

Readers are cautioned to refer to the manufacturers' test kit inserts for specific details. Information in this appendix represents general conditions for comparative purposes.

Endocervical swabs/urethral swabs from males

Indications

Screening
- Females: When pelvic examination is indicated
- Males: Urine might be more acceptable to asymptomatic males
Endocervicitis
Urethritis (males)
Diseases at other anatomic locations possibly caused by sexually acquired C. trachomatis infection
- Pelvic inflammatory disease
- Urethral syndrome
- Bartholinitis
- Epididymitis
- Perihepatitis (Fitz-Hugh-Curtis syndrome) (females)
- Proctitis
- Reactive arthritis/Reiter syndrome
- Conjunctivitis
Not recommended for prepubertal children

Test selection

Nucleic acid amplification tests (NAATs)
- Preferred because of high sensitivity relative to other tests
Nonculture/non-NAAT
- Recommended when a NAAT is not available or not economical
Culture
- Preferred when an isolate is needed (e.g., sexual abuse or treatment failure)
Point-of-care tests
- Recommended only when the patient is likely to be lost to follow-up and when the test will be performed while the patient waits for results and possible treatment
Additional testing is recommended after an initial positive screening test if a low positive predictive value can be expected or if a false-positive result would have serious psychosocial or legal consequences

Urethral swabs from females

Indication

Used with endocervical swab to increase sensitivity of culture for screening
Urethral syndrome

Test selection

Culture
- Increases sensitivity of culture of endocervical swab for screening by ≤23%*
- Among C. trachomatis-infected persons, dysuria is associated with a high frequency of a positive urethral culture†
Nonculture tests are not recommended

Urine

Indication

Females: Screening or testing
Males: Screening

Test selection

NAAT
- Recommended on the basis of increased sensitivity and ease of use
- For males, sensitivity with urine has been lower than with urethral swab in the majority of studies,§ but not all¶
- Other tests are not recommended because of low sensitivity and, in the case of enzyme immunoassay (EIA) and lipopolysaccharide (LPS)-specific direct fluorescent antibody (DFA) tests, lower specificity
- Additional testing is recommended after an initial positive screening test if a low positive predictive value can be expected or if a false-positive result would have serious psychosocial or legal consequences

Vaginal swabs, postmenarcheal adolescents and adults

Indication

Screening/testing of women when pelvic examination is not otherwise indicated

Test selection

No test is recommended for use with vaginal swab specimens
- The Food and Drug Administration (FDA) has not cleared any nonculture test for use with vaginal specimens
- NAAT
  Additional review is needed before a recommendation can be made; however, in multiple studies, sensitivity and specificity with a provider-or client-collected vaginal swab has been similar to screening with endocervical or urine specimens
  Additional testing is recommended after an initial positive screening test if a low positive predictive value can be expected or if a positive result would have serious psychosocial or legal consequences
- Culture
  Not recommended for adults because of suboptimal sensitivity
- Other tests are not recommended because of low sensitivity and, in case of EIA and LPS-specific DFA, low specificity

Vaginal swabs, prepubescent females

Indication

Possible sexual abuse, children

Test selection

Culture
- Preferred for possibly sexually abused children because of presence of vaginal epithelium that is susceptible to C. trachomatis infection, high specificity, and ability to retain isolate for additional testing
FDA has not cleared any nonculture test for use with vaginal specimens
NAAT
- When culture is not available, certain C. trachomatis specialists support using a NAAT if a positive result can be verified by another NAAT
Other tests are not recommended because of low sensitivity and, in the case of EIA and LPS-specific DFA, low specificity

Rectal swabs

Indication

Patients with history of receptive anal intercourse
Proctitis
Possible sexual abuse, children

Test selection

Culture
- Preferred when an isolate is needed (e.g., sexual abuse)
- Sensitivity not well-defined; high specificity, especially if C. trachomatis specific stain is used
DFA
- FDA-cleared for use with rectal specimens
- Limited evaluation in published studies
- Sensitivity not well-defined; potentially high specificity if C. trachomatis specific stain is used
Other tests are not recommended
- NAAT
  Although cross-reactivity with other rectal bacteria has not been reported for NAATs, they have received only limited evaluation in published studies

Pharyngeal swabs

Indication

Patients concerned regarding exposure during fellatio or cunnilingus
Newborns or infants (nasopharyngeal specimens)
- Neonatal conjunctivitis
- Pneumonia consistent with C. trachomatis etiology
Possible sexual abuse, children

Test selection

Culture
- Preferred method
- Necessary when an isolate is needed (e.g., sexual abuse)
- Sensitivity not well-defined; high specificity, including if C. trachomatis-specific stain is used
DFA
- FDA-cleared for use with pharyngeal specimens
- Limited evaluation in published studies
- Sensitivity not well-defined; potentially high specificity if C. trachomatis-specific stain is used
Other tests are not recommended
- NAAT
  Although cross-reactivity with other pharyngeal bacteria has not been reported for NAATs, they have received only limited evaluation in published studies**

Conjunctival swabs

Indication

Conjunctivitis among adults
Newborns or infants
- Neonatal conjunctivitis
- Pneumonia consistent with C. trachomatis etiology

Test selection

Culture
- Preferred, when available, because of high sensitivity and specificity
EIA, nucleic acid probe, and DFA tests
- EIA, nucleic acid probe, and DFA tests that are FDA-cleared for use with conjunctival specimens have had uniformly high sensitivities with conjunctival specimens from newborns;†† evaluation studies are more limited for conjunctival specimens from adults with conjunctivitis
- Specificities of tests on conjunctival specimens have also been high,†† although the potential for cross-reaction with other bacteria exists for EIA and for culture and DFA if used with stains that are not specific for C. trachomatis
Other tests are not recommended

* Source: Jones RB, Katz BP, Van der Pol B, Caine VA, Batteiger BE, Newhall WJ. Effect of blind passage and multiple sampling on recovery of Chlamydia trachomatis from urogenital specimens. J Clin Microbiol 1986;24:1029–33.

† Source: Paavonen J. Chlamydia trachomatis-induced urethritis in female partners of men with nongonococcal urethritis. Sex Transm Dis 1979;6:69–71.

§ Sources: Stary A, Schuh E, Kerschbaumer M, Gotz B, Lee H. Performance of transcription-mediated amplification and ligase chain reaction assays for detection of chlamydial infection in urogenital samples obtained by invasive and noninvasive methods. J Clin Microbiol 1998;36:2666–70. Crotchfelt KA, Welsh LE, DeBonville D, Rosenstraus M, Quinn TC. Detection of Neisseria gonorrhoeae and Chlamydia trachomatis in genitourinary specimens from men and women by a coamplification PCR assay. J Clin Microbiol 1997;35:1536–40. Buimer M, van Doornum GJJ, Ching S, et al. Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by ligase chain reaction-based assays with clinical specimens from various sites: implications for diagnostic testing and screening. J Clin Microbiol 1996;34:2395–2400. Carroll KC, Aldeen WE, Morrison M, Anderson R, Lee D, Mottice S. Evaluation of the Abbott LCx Ligase Chain Reaction Assay for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in urine and genital swab specimens from a sexually transmitted disease clinic population. J Clin Microbiol 1998;36:1630–3. Ferrero DV, Meyers HN, Schultz DE, Willis SA. Performance of the Gen-Probe AMPLIFIED Chlamydia Trachomatis Assay in detecting Chlamydia trachomatis in endocervical and urine specimens from women and urethral and urine specimens from men attending sexually transmitted disease and family planning clinics. J Clin Microbiol 1998;36:3230–3. Ossewaarde JM, van Doornum GJJ, Buimer M, Choueiri B, Stary A. Differences in the sensitivity of the Amplicor Chlamydia trachomatis PCR assay. Genitourin Med 1997;73:207–11. Puolakkainen M, Hiltunen-Back E, Reunala T, et al. Comparison of performances of two commercially available tests, a PCR assay and a ligase chain reaction test, in detection of urogenital Chlamydia trachomatis infection. J Clin Microbiol 1998;36:1489–93. Stary A, Choueiri B, Hörting-Müller I, Halisch P, Teodorowicz L. Detection of Chlamydia trachomatis in urethral and urine samples from symptomatic and asymptomatic male patients by the polymerase chain reaction. Eur J Clin Microbiol Infect Dis 1996;15:465–71.

¶ Sources: Van der Pol B, Quinn TC, Gaydos CA, et al. Multicenter evaluation of the AMPLICOR and automated COBAS AMPLICOR CT/NG tests for detection of Chlamydia trachomatis. J Clin Microbiol 2000;38:1105–12. Toye B, Peeling RW, Jessamine P, Claman P, Gemmill I. Diagnosis of Chlamydia trachomatis infections in asymptomatic men and women by PCR assay. J Clin Microbiol 1996;34:1396–1400. Vincelette J, Schirm J, Bogard M, et al. Multicenter evaluation of the fully automated COBAS AMPLICOR PCR test for detection of Chlamydia trachomatis in urogenital specimens. J Clin Microbiol 1999;37:74–80. Wiesenfeld HC, Uhrin M, Dixon BW, Sweet RL. Diagnosis of male Chlamydia trachomatis urethritis by polymerase chain reaction. Sex Transm Dis 1994;21:268–71. Young H, Moyes A, Horn K, Scott GR, Patrizio C, Sutherland S. PCR testing of genital and urine specimens compared with culture for the diagnosis of chlamydial infection in men and women. Int J STD AIDS 1998;9:661–5.

**Source: Hammerschlag MR, Roblin PM, Gelling M, Tsumura N, Jule JE, Kutlin A. Use of polymerase chain reaction for the detection of Chlamydia trachomatis in ocular and nasopharyngeal specimens from infants with conjunctivitis. Pediatr Infect Dis J 1997;16:293–7.

††Sources: Hammerschlag MR. Diagnosis of chlamydial infection in the pediatric population. Immunol Invest 1997;26:151–6. Hammerschlag MR. Chlamydia trachomatis in children. Pediatr Ann 1994;23:349–53. Hammerschlag MR, Roblin PM, Gelling M, Worku M. Comparison of two enzyme immunoassays to culture for the diagnosis of chlamydial conjunctivitis and respiratory infections in infants. J Clin Microbiol 1990;28:1725–7. Hammerschlag MR, Roblin PM, Cummings C, Williams TH, Worku M, Howard LV. Comparison of enzyme immunoassay and culture for diagnosis of chlamydial conjunctivitis and respiratory infections in infants. J Clin Microbiol 1987;25:2306–8.

Table of Contents

Date last reviewed: October 18, 2002
Content Source: MMWR October 18, 2002 / Vol. 51 / No. RR--15
Content Owner: Division of STD Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention