Chlamydia and LGV guide: Screening and diagnostic testing

Screening and diagnostic testing guidance for Chlamydia trachomatis infections (including lymphogranuloma venereum (LGV)).

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Screening

For the purpose of the Public Health Agency of Canada's STBBI Guides for health professionals, screening is defined as a process aimed at detecting a condition in an asymptomatic person. Consult the following tables for more information on different types of screening methods for sexually transmitted and blood-borne infections (STBBI) and the ways they can be implemented:

Types of screening
Screening methods Description
Universal screening Screening in all sexually active persons with a new or multiple partners, and/or upon request of the individual.
Targeted/risk-based/selective screening Screening based on a characteristic associated with increased risk of the condition being detectedFootnote 1.
Ways to implement screening
Implementation Description
Opt-in screening Offering testing to individuals who agree.
Opt-out screening Testing is done automatically unless the patient declines.
Opportunistic screening Offering screening when an individual accesses health services and has not undergone recent STBBI testing.

C. trachomatis

Due to the asymptomatic nature of chlamydia, many individuals infected with C. trachomatis may be unaware of their status. As a result, undiagnosed and untreated infections may lead to serious health complications such as pelvic inflammatory disease and epididymitis and may contribute to the spread of infectionFootnote 2 Footnote 3 Footnote 4. Screening for chlamydia is essential for detecting and treating asymptomatic infections and preventing transmission.

The use of non-invasive samples (i.e., urine or self-obtained vaginal swab) can increase acceptance of screening for C. trachomatis infections. Depending on type of sexual activity, it may be necessary to collect specimens from multiple anatomical sites.

Adults and adolescents under the age of 30 years

Offer universal annual screening in all sexually active persons under the age of 30 yearsFootnote 5.

Consider the following options to increase screening uptake:

Adults and adolescents with multiple partners or a new partner

For persons with multiple sexual partners or a new partner since last tested, offer screening every three to six monthsFootnote 5.

High prevalence groups and communities

Consider implementing an opt-out approach to chlamydia screening as frequently as every 3 months in populations or communities experiencing high prevalence of chlamydia (and other STBBI), such as:

Consider aligning screening with other health services (i.e., opportunistic screening) such as HIV or addiction careFootnote 5.

Consider local epidemiology, travel history and individual risk factors when determining which groups/communities to target for screeningFootnote 5.

Pregnant people

Screen all pregnant people during the first trimester or at the first antenatal visit. Rescreen during the third trimesterFootnote 6.

Screen pregnant people at the time of labour in any of the following situations:

Neonates

Screen neonates exposed to chlamydia during pregnancy, labour, or delivery.

LGV

Routine LGV genotyping of asymptomatic chlamydia infections is not recommended. Consider LGV genotyping when an asymptomatic rectal chlamydia infection is diagnosed in gay, bisexual and other men who have sex with men (gbMSM) with risk factors for LGV.

Other sexually transmitted and blood-borne infections (STBBI)

Screening for sexually transmitted and blood-borne infections (STBBI) varies by age, gender, sex, medical and sexual history. Screen anyone who presents with STBBI risk factors and treat as appropriate to prevent transmission and reinfection.

People with N. gonorrhoeae often have a co-infection with C. trachomatisFootnote 7 Footnote 8.

Infection with C. trachomatis can increase the risk of acquisition and transmission of human immunodeficiency virus (HIV)Footnote 9 Footnote 10 Footnote 11.

People being evaluated or treated for a chlamydia infection should be screened for:

Because of high rates of co-infection, people being evaluated or treated for LGV should be screened for:

Diagnostic testing

C. trachomatis

Clinical presentation and sexual history determine which specimens should be collected and the type of test to useFootnote 7 Footnote 8.

Nucleic acid amplification tests (NAAT) are the most sensitive test for C. trachomatis Footnote 13 Footnote 14. Culture for C. trachomatis is no longer routinely available in Canada. Results are highly dependent on the type of test, specimen collection/transport and laboratory expertise. Consult with local laboratory regarding available tests, specimen collection and test performance.

NAAT does not differentiate between LGV and non-LGV genotypes. Use NAAT whenever possible for urine and urethral, cervical or vaginal swabs. Check with local laboratory about the availability of NAAT for testing of extra-genital specimens. Validated NAAT for rectal specimens are available in most jurisdictions, if unavailable check if culture is still available. Consult with provincial and territorial guidelines or local laboratory regarding the use of NAAT for medico-legal purposes.

Based on expert opinion, that NAAT can detect small amounts of DNA or RNA (inoculum), post-exposure testing using NAAT can be done without waiting for 48 hours.

For people with suspected LGV, if there has been travel to regions where chancroid ( Haemophilus ducreyi) and donovanosis/granuloma inguinale (Klebsiella granulomatis) are endemic, consider these conditions as differential diagnoses.

Recommended specimens and tests for C. trachomatis

Asymptomatic people
Test Specimens for asymptomatic males Specimens for asymptomatic females
NAAT First-void urine

Vaginal swab, self-obtained or collected by a clinician

or

First-void urine

or

Cervical swab

  Based on history, collect conjunctival, pharyngeal and/or rectal swabs

Note: Urine specimens should be first-void urine (initial 10 to 20 mL of the urine stream). Ideally, the person should not have voided for at least two hours prior to urine or urethral swab specimen collection. More recent voiding does not preclude testing Footnote 15.

Symptomatic people

Physical examination is essential when a sexually transmitted infection (STI) is suspected. Collect specimens based on clinical presentation and sexual history, prior to treatment.

Test Specimens for symptomatic males Footnote 15 Specimens for symptomatic females Footnote 15
NAAT
  • First-void urine
  • Urethral swab
  • Rectal swab
  • Pharyngeal swab
  • First-void urine
  • Cervical swab
  • Vaginal swab
  • Rectal swab
  • Pharyngeal swab
 
  • Swab of the lesion
  • Fluid from buboes
  • Conjunctival swab

Due to high rates of concomitant infection, also collect specimens for the diagnosis of gonococcal infections by NAAT and cultureFootnote 7. NAAT can detect both C. trachomatis and N. gonorrhoeae from a single specimen. Consult the table in the Culture section of the Gonorrhea Guide for when to collect culture specimens for N. gonorrhoeae.

LGV

LGV diagnosis is not straightforward. It is often based on history and clinical presentation, supported by laboratory testing. Clinicians should have a high index of suspicion for LGV in people who present with consistent signs/symptoms (e.g., proctitis and/or marked inguinal or femoral lymphadenopathy or buboes) and/or if their history suggests exposure.

Identification of C. trachomatis in bubo fluid is highly suggestive of LGV, even prior to or without identification of LGV genotypes. Buboes caused by LGV usually contain a small amount of milky fluid. Aspirate buboes through healthy skin: An injection of 2 to 5 mL sterile saline may be required.

Genotyping

Genotyping of positive specimens for C. trachomatis is necessary for a definitive diagnosis of LGV.

C. trachomatis-positive specimens from people with symptoms compatible with LGV and from sexual partners of people diagnosed with LGV should be forwarded to a provincial/territorial laboratory or the National Microbiology Laboratory (NML) for LGV genotyping.

Published data on LGV in gbMSM have found that few urine samples or urethral swabs test positive for LGV when C. trachomatis is identifiedFootnote 16 Footnote 17 Footnote 18 Footnote 19 Footnote 20.

For gbMSM with risk factors for LGV, consider LGV genotyping of rectal specimens with positive C. trachomatis results. Although earlier studies identified rectal LGV primarily in symptomatic peopleFootnote 16 Footnote 17 Footnote 21, a 2017 study from the Netherlands found that a high proportion of chlamydia-positive rectal specimens tested positive for LGV in asymptomatic gbMSMFootnote 18.

Anoscopy/sigmoidoscopy/proctoscopy

Anoscopy/sigmoidoscopy/proctoscopy may reveal a pattern that resembles ulcerative colitis and/or granular or ulcerative proctitis in people with LGVFootnote 22.

Serology

Serology is not recommended for LGV diagnosis, due to cross-reactions with other C. trachomatis species and difficulties interpreting variations in titres. Because of the invasive nature of LGV, serology titres are generally significantly higher in LGV than in non-LGV chlamydia infections. Although high-titre serology is suggestive of LGV infection, it does not allow for a definitive diagnosis. Conversely, low-titre serology does not eliminate the possibility of current or past LGV infection. Because the duration of antibody response has not been defined, serology should not be used to assess treatment response.

References

Footnote 1

Speechley M, Kunnilathu A, Aluckal E, Balakrishna MS, Mathew B, George EK. Screening in Public Health and Clinical Care: Similarities and Differences in Definitions, Types, and Aims - A Systematic Review. J Clin Diagn Res. 2017;11(3):LE01-LE04. doi:10.7860/JCDR/2017/24811.9419

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Footnote 2

Choudhri Y, Miller J, Sandhu J, Leon A, Aho J. Chlamydia in Canada, 2010-2015. Can Commun Dis Rep. 2018 Feb 1;44(2):49-54. https://doi.org/10.14745/ccdr.v44i02a03

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Footnote 3

Navarro C, Jolly A, Nair R, Chen Y. Risk Factors for Genital Chlamydial Infection: A Review. Canadian Journal of Infectious Diseases and Medical Microbiology. 2002;13(3):195-207.

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Footnote 4

Public Health Agency of Canada. Chlamydia and LGV guide: Risk factors and clinical manifestations. 2024; Available at: https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines/chlamydia-lgv/risk-factors-clinical-manifestation.html

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Footnote 5

National Advisory Committee on Sexually Transmitted and Blood-Borne Infections. An Advisory Committee Statement (ACS). National Advisory Committee on Sexually Transmitted and Blood-Borne Infections (NAC-STBBI). Recommendations on Screening for Chlamydia trachomatis and Neisseria gonorrhoeae for non-pregnant adults/adolescents, September, 2024 (pending publication).

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Footnote 6

National Advisory Committee on Sexually Transmitted and Blood-Borne Infections. An Advisory Committee Statement (ACS) National Advisory Committee on Sexually Transmitted and Blood-Borne Infections (NAC-STBBI). Recommendations on Screening for Neisseria Gonorrhoeae and Chlamydia Trachomatis in Pregnancy, October 2022. Retrieved from: https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines/national-advisory-committee-stbbi/statements/recommendations-screening-chlamydia-trachomatis-neisseria-gonorrhoeae-pregnancy.html.

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Footnote 7

Creighton S, Tenant-Flowers M, Taylor C, Miller R, Low N. Co-infection with gonorrhoea and chlamydia: how much is there and what does it mean? Int J STD AIDS 2003;14(2):109-113.

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Footnote 8

Lyss SB, Kamb ML, Peterman TA, Moran JS, Newman DR, Bolan G, et al. Chlamydia trachomatis among patients infected with and treated for Neisseria gonorrhoeae in sexually transmitted disease clinics in the United States. Ann Intern Med 2003;139(3):178-185.

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Footnote 9

Fransen L, Avonts D, Piot P. Treatment of genital chlamydial infection with ofloxacin. Infection 1986;14(suppl 4):S318.

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Footnote 10

Batteiger B, Jones R, White A. Efficacy and safety of ofloxacin in the treatment of nongonococcal sexually transmitted disease.. Am.J.Med. 1989;87(6C):75S.

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Footnote 11

Nayagam A, Ridgway G, Oriel J. Efficacy of ofloxacin in the treatment of non-gonococcal urethritis in men and genital infections caused by Chlamydia trachomatis in men and women. J Antimicrob Chemother 1988;22(suppl C):155.

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Footnote 12

Boutin CA, Venne S, Fiset M, Fortin C, Murphy D, Severini A, et al. Lymphogranuloma venereum in Quebec: Re-emergence among men who have sex with men. Can Commun Dis Rep 2018 Feb 1;44(2):55-61.

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Footnote 13

Association of Public Health Laboratories. Laboratory Diagnostic Testing for Chlamydia trachomatis and Neisseria gonorrhoeae. Expert Consultation Meeting Summary Report January 13-15, 2009.

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Footnote 14

Kapala J, Biers K, Cox M, Kamionka M, Sumner J, Toor R, et al. Aptima Combo 2 testing detected additional cases of Neisseria gonorrhoeae infection in men and women in community settings. J Clin Microbiol 2011 May;49(5):1970-1971.

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Footnote 15

Centers for Disease Control and Prevention. Recommendations for the laboratory-based detection of Chlamydia trachomatis and Neisseria gonorrhoeae--2014. MMWR Recomm Rep 2014 Mar 14;63(RR-02):1-19.

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Footnote 16

Nieuwenhuis RF, Ossewaarde JM, Götz HM, Dees J, Thio HB, Thomeer MG, et al. Resurgence of lymphogranuloma venereum in Western Europe: an outbreak of Chlamydia trachomatis serovar l2 proctitis in The Netherlands among men who have sex with men. Clinical infectious diseases 2004;39(7):996-1003.

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Footnote 17

Ward H, Alexander S, Carder C, Dean G, French P, Ivens D, et al. The prevalence of lymphogranuloma venereum infection in men who have sex with men: results of a multicentre case finding study. Sex Transm Infect 2009 Jun;85(3):173-175.

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Footnote 18

de Vrieze NHN, Versteeg B, Bruisten SM, van Rooijen MS, van der Helm JJ, de Vries HJC. Low Prevalence of Urethral Lymphogranuloma Venereum Infections Among Men Who Have Sex With Men: A Prospective Observational Study, Sexually Transmitted Infection Clinic in Amsterdam, the Netherlands. Sex Transm Dis 2017 Sep;44(9):547-550.

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Footnote 19

Desclaux A, Touati A, Neau D, Laurier-Nadalie C, Bebear C, de Barbeyrac B, et al. Extra-rectal lymphogranuloma venereum in France: a clinical and molecular study. Sex Transm Infect 2018 Feb;94(1):3-8.

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Footnote 20

Annan NT, Sullivan AK, Nori A, Naydenova P, Alexander S, McKenna A, et al. Rectal chlamydia--a reservoir of undiagnosed infection in men who have sex with men. Sex Transm Infect 2009 Jun;85(3):176-179.

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Footnote 21

Saxon C, Hughes G, Ison C, UK LGV Case-Finding Group. Asymptomatic Lymphogranuloma Venereum in Men who Have Sex with Men, United Kingdom. Emerg Infect Dis 2016 Jan;22(1):112-116.

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Footnote 22

Quinn TC, Goodell SE, Mkrtichian E, Schuffler MD, Wang S, Stamm WE, et al. Chlamydia trachomatis proctitis. N Engl J Med 1981;305(4):195-200.

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