Gonorrhea guide: Screening and diagnostic testing

Screening and diagnostic testing guidance for Neisseria gonorrhoeae infections. The following information on collecting swabs for culture in addition to NAAT consist of an interim guidance from the National Advisory Committee on Sexually Transmitted and Blood-Borne Infections. Final recommendations will be available after the completion of a review currently underway.

Screening

Screening for N. gonorrhoeae is essential for detecting and treating asymptomatic infections and preventing transmission. Depending on the type of sexual activity, it may be necessary to collect specimens from multiple anatomical sites.

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 detected^{Footnote 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.

Adults and adolescents under the age of 30 years

Offer universal annual screening in all sexually active persons under the age of 30 years^{Footnote 2}.

Consider the following options to increase screening uptake^{Footnote 2}:

Opportunistic screening
Increasing accessibility and normalizing testing through strategies such as outreach testing and opt-out screening
Facilitating sample collection through strategies such as non-invasive collection specimens, including self-sampling

Adults and adolescents with multiple partners or a new partners

For persons with multiple sexual partners or a new partner since last tested, offer screening every three to six months^{Footnote 2}.

High prevalence groups and communities

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

Gay, bisexual, and other men who have sex with men
People living with HIV
People who are or have been incarcerated
People who use substances or access addiction services
Some Indigenous communities^{Footnote 2}

Consider aligning screening with other health services (i.e., opportunistic screening) such as HIV or addiction care^{Footnote 2}.

Consider local epidemiology, travel history and individual patient risk factors when determining which groups/communities to target for screening^{Footnote 2}.

Pregnant people

Screen all pregnant people during their first trimester or at the first antenatal visit. Rescreen during the third trimester^{Footnote 3}.

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

No prenatal screening has occurred (no valid results are available at the time of labour)
Third trimester screening has not occurred.
A positive test result was obtained for N. gonorrhoeae or C. trachomatis during pregnancy without appropriate follow-up, including treatment and a test-of-cure^{Footnote 3}

Neonates

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

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. trachomatis^{Footnote 4}^{Footnote 5}^{Footnote 6}. Gonorrhea can increase the risk of HIV acquisition and transmission^{Footnote 7}^{Footnote 8}^{Footnote 9}.

People being evaluated or treated for gonorrhea should be screened for:

Chlamydia
Syphilis
HIV, as per the recommendations in the HIV Screening and Testing Guide

If risk factors are present and if clinically indicated, consider screening for:

Offer vaccination for hepatitis B (HBV), hepatitis A (HAV), human papillomavirus (HPV) and mpox as per the Canadian Immunization Guide. Refer to provincial or territorial vaccination schedules for more information.

Diagnostic testing

Clinical presentation and sexual history determine which specimens should be collected and the type of test to use. Laboratory tests for the diagnosis of gonorrhea may include culture, NAAT and microscopy (Gram stain).

Note: The sensitivity and specificity of these tests varies widely. Consult your local laboratory for available tests, specimen collection and test performance.

Nucleic acid amplification tests (NAAT)

NAAT are the most sensitive tests for N. gonorrhoeae^{Footnote 10}^{Footnote 11} and may increase the number of cases diagnosed^{Footnote 11}^{Footnote 12}.

NAAT may be done without waiting 48 hours post-exposure. This is based on expert opinion that NAAT can detect small amounts of DNA or RNA (inoculum). Validated NAAT can be used to detect rectal and pharyngeal infections.

Some NAAT may generate false positive results due to possible cross-reaction with other Neisseria species. If a false positive result is suspected, consult with your laboratory for further guidance.

Culture

Although culture is less sensitive than NAAT, it provides antimicrobial susceptibilities, which is important for case management and public health monitoring of antimicrobial resistance (AMR) patterns and trends^{Footnote 13}^{Footnote 14}^{Footnote 15}^{Footnote 16}^{Footnote 17}^{Footnote 18}^{Footnote 19}.

Important considerations for culture:

Successful culture requires proper collection and transportation of appropriate specimens^{Footnote 19} ^{Footnote 20} ^{Footnote 21}.
Culture specimens collected within 48 hours of exposure may give false negative results.
Consult with your local Public Health Laboratory for guidance on specimen collection and transportation.

When to collect specimens for NG culture

Collect specimens for culture together with NAAT at initial assessment^{Footnote 19}:
- In the presence of symptoms compatible with cervicitis, urethritis, pelvic inflammatory disease (PID), epididymo-orchitis, proctitis or pharyngitis
- In pregnant individuals
- When an asymptomatic individual is notified as a contact of an individual infected with N. gonorrhoeae
- When sexual abuse/sexual assault is suspected (this may vary according to legal and medical contexts of the jurisdiction)
- If the infection might have been acquired in countries or areas with high rates of AMR^{Footnote *}
Collect specimens for culture prior to treatment when NG infection was detected by NAAT only, as long as it does not delay treatment^{Footnote 19}.
Refer to the Treatment and follow-up tab of the Gonorrhea Guide for more information regarding when to collect culture specimens for test-of-cure.

Note:

Footnote *

N. gonorrhoeae resistant strains have been reported in Canada, Japan, Europe and Australia, with many associated with travel to South-East Asia^{Footnote 19} ^{Footnote 22} ^{Footnote 23} ^{Footnote 24} ^{Footnote 25} ^{Footnote 26} ^{Footnote 27} ^{Footnote 28} ^{Footnote 29}.

Return to footnote * referrer

Gram stain

The presence of Gram-negative intracellular diplococci (GNID) seen on direct microscopic examination of urethral smears is highly predictive of N. gonorrhoeae in symptomatic males^{Footnote 21}.

The sensitivity and specificity of the Gram stain depends on the type of specimen^{Footnote 21}:

Urethral specimens from symptomatic males have a sensitivity and specificity of 95%, but are less sensitive in asymptomatic males (50-75%)^{Footnote 30}.
Endocervical specimens for adult females are not routinely recommended as the sensitivity is 45–65% and the specificity is 90%.
Gram stain is not suitable for pharyngeal and rectal specimens.

Recommended specimens and tests for N. gonorrhoeae

Specimens and tests for urogenital sites (urethral, endocervical, vaginal)

People without urogenital symptoms

NAAT is the screening test of choice. Consult the table in the Culture section of the Gonorrhea Guide for when to collect specimens for NG culture.

Test	Urogenital specimens for asymptomatic males^{Footnote 12}	Urogenital specimens for asymptomatic females
NAAT	First-void urine or Urethral swab	Vaginal swab, self-obtained or collected by a clinician or Cervical swab or First-void urine

Important considerations:

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 31}.
First-void urine, also called first-catch urine (FCU), is preferred for asymptomatic males over a urethral swab for NAAT.
NAAT for N. gonorrhoeae using vaginal swabs may identify more infections in females than cervical swabs, urethral swabs or urine^{Footnote 32}. Vaginal swabs may be collected without a speculum exam.
Self-collected vaginal swabs are more acceptable to females than provider-collected vaginal swabs. Check whether your local laboratory accepts self-collected vaginal swabs. Acceptability of urine testing is also high.

People with urogenital symptoms

Physical examination is essential when an STI is suspected. Collect specimens based on clinical presentation and sexual history, prior to treatment.

Due to high rates of concomitant infection, specimens should be collected for the diagnosis of both gonococcal and chlamydia infections by NAAT^{Footnote 5}^{Footnote 12}. 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 specimens for NG culture.

Test	Urogenital specimens for symptomatic males	Urogenital specimens for symptomatic females
NAAT	First-void urine or Urethral swab	First-void urine or Vaginal swab or Cervical swab
Gram stain	Urethral swab	Not routinely recommended
Culture	Urethral swab	Cervical swab

Important considerations:

It is preferable that the person not have voided for at least 2 hours prior to urine or urethral swab collection; however, this is not mandatory^{Footnote 33}^{Footnote 34}.

Specimens and tests for extragenital sites (pharyngeal and rectal)

Consider collecting specimens for both culture and NAAT and consult the table in the Culture section of the Gonorrhea Guide for additional considerations for culture.

Collect pharyngeal specimens for the following people:

All females with a history of performing oral sex
All males with a history of performing oral sex who are at high risk of exposure (gbMSM, multiple sexual partners or sex with a partner who is at high risk of infection)

Collect rectal specimens for the following people:

People with a history of receptive anal intercourse, regardless of history of condom use
People with rectal symptoms^{Footnote 35}

Note:

Consider rectal screening in all gbMSM regardless of history of receptive anal intercourse (RAI)^{Footnote 36} ^{Footnote 37} ^{Footnote 38}.

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

Return to footnote 1 referrer

Footnote 2

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. Retrieved from: (pending publication)

Return to footnote 2 referrer

Footnote 3

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.

Return to footnote 3 referrer

Footnote 4

Creighton S, Tenant-Flowers M, Taylor CB, 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. doi:10.1258/095646203321156872

Return to footnote 4 referrer

Footnote 5

Lyss SB, Kamb ML, Peterman TA, 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.

Return to footnote 5 referrer

Footnote 6

Mayor MT, Roett MA, Uduhiri KA. Diagnosis and management of gonococcal infections [published correction appears in Am Fam Physician. 2013 Feb 1;87(3):163]. Am Fam Physician. 2012;86(10):931-938.

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Footnote 7

Laga M, Manoka A, Kivuvu M, et al. Non-ulcerative sexually transmitted diseases as risk factors for HIV-1 transmission in women: results from a cohort study. AIDS. 1993;7(1):95-102.

Return to footnote 7 referrer

Footnote 8

Johnson LF, Lewis DA. The effect of genital tract infections on HIV-1 shedding in the genital tract: a systematic review and meta-analysis. Sex Transm Dis. 2008;35(11):946-959.

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Footnote 9

Fleming DT, Wasserheit JN. From epidemiological synergy to public health policy and practice: the contribution of other sexually transmitted diseases to sexual transmission of HIV infection. Sex Transm Infect. 1999;75(1):3-17.

Return to footnote 9 referrer

Footnote 10

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

Return to footnote 10 referrer

Footnote 11

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

Return to footnote 11 referrer

Footnote 12

Papp JR, Schachter J, Gaydos CA, Van Der Pol B.Centers for Disease Control and Prevention. Recommendations for the laboratory-based detection of Chlamydia trachomatis and Neisseria gonorrhoeae--2014. MMWR Recomm Rep. 2014;63(RR-02):1-19.

Return to footnote 12 referrer

Footnote 13

Centers for Disease Control and Prevention (CDC). Cephalosporin susceptibility among Neisseria gonorrhoeae isolates--United States, 2000-2010. MMWR Morb Mortal Wkly Rep. 2011 Jul 8;60(26):873-7. PMID: 21734634.

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Footnote 14

Dillon JA. Sustainable antimicrobial surveillance programs essential for controlling Neisseria gonorrhoeae superbug. Sex Transm Dis. 2011;38(10):899-901. doi:10.1097/OLQ.0b013e318232459b

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Footnote 15

Kirkcaldy RD, Ballard RC, Dowell D. Gonococcal resistance: are cephalosporins next?. Curr Infect Dis Rep. 2011;13(2):196-204.

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Footnote 16

MacDonald NE, Stanbrook MB, Flegel K, Hébert PC, Rosenfield D. Gonorrhea: what goes around comes around. CMAJ. 2011;183(14):1567.

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Footnote 17

Tapsall JW, Ndowa F, Lewis DA, Unemo M. Meeting the public health challenge of multidrug- and extensively drug-resistant Neisseria gonorrhoeae. Expert Rev Anti Infect Ther. 2009;7(7):821-834.

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Footnote 18

Unemo M, Shipitsyna E, Domeika M; Eastern European Sexual and Reproductive Health (EE SRH) Network Antimicrobial Resistance Group. Recommended antimicrobial treatment of uncomplicated gonorrhoea in 2009 in 11 East European countries: implementation of a Neisseria gonorrhoeae antimicrobial susceptibility programme in this region is crucial. Sex Transm Infect. 2010;86(6):442-444.

Return to footnote 18 referrer

Footnote 19

National Advisory Committee on Sexually Transmitted and Blood-Borne Infections (NAC-STBBI). Interim guidance for the treatment of uncomplicated gonococcal infections, September, 2023. Ottawa: Public Health Agency of Canada. 2023. Retrieved from: https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines/national-advisory-committee-stbbi/statements/interim-guidance-treatment-uncomplicated-gonococcal-infections.html

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Footnote 20

Ng LK, Martin IE. The laboratory diagnosis of Neisseria gonorrhoeae. Can J Infect Dis Med Microbiol. 2005;16(1):15-25. 18.

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Footnote 21

Ison C LD. Gonorrhea. In: Morse S, Ballard R, Holmes K, Moreland A, ed. Atlas of sexually transmitted diseases and AIDS. 4th ed ed. Netherlands: Elsevier; 2010:24-39.

Return to footnote 21 referrer

Footnote 22

Lahra MM, Martin I, Demczuk W, et al. Cooperative Recognition of Internationally Disseminated Ceftriaxone-Resistant Neisseria gonorrhoeae Strain. Emerg Infect Dis. 2018;24(4):735-740. doi:10.3201/eid2404.171873

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Footnote 23

Lefebvre B, Martin I, Demczuk W, et al. Ceftriaxone-Resistant Neisseria gonorrhoeae, Canada, 2017. Emerg Infect Dis. 2018; 24(2):381-383. doi:10.3201/eid2402.171756

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Footnote 24

Sawatzky P, Lefebvre B, Diggle M, Hoang L, Wong J, Patel S, Van Caessele P, Minion J, Garceau R, Jeffrey S, Haldane D, Lourenco L, Gravel G, Mulvey M, Martin I. Antimicrobial susceptibilities of Neisseria gonorrhoeae in Canada, 2021. Can Commun Dis Rep 2023;49(9):388−97. https://doi.org/10.14745/ccdr.v49i09a05

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Footnote 25

Nakayama S, Shimuta K, Furubayashi K, Kawahata T, Unemo M. Strain with a Novel Mosaic penA Gene Isolated in Japan. N Engl J Med. 2016;60(7):4339-4341. doi:10.1128/AAC.00504-16.

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Footnote 26

Chen SC, Yuan LF, Zhu XY, van der Veen S, Yin YP. Sustained transmission of the ceftriaxone-resistant Neisseria gonorrhoeae FC428 clone in China. J Antimicrob Chemother. 2020;75(9):2499-2502. doi:10.1093/jac/dkaa196.

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Footnote 27

Terkelsen D, Tolstrup J, Johnsen CH, Lund O, Kiellberg Larsen H, Worning P, et al. Multidrug-resistant Neisseria gonorrhoeae infection with ceftriaxone resistance and intermediate resistance to azithromycin, Denmark, 2017. Eurosurveillance. 2017;22(42):1-4. doi:10.2807/1560-7917.ES.2017.22.42.17-00659.

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Footnote 28

Golparian D, Rose L, Lynam A, Mohamed A, Bercot B, Ohnishi M, et al. Multidrug-resistant Neisseria gonorrhoeae isolate, belonging to the internationally spreading Japanese FC428 clone, with ceftriaxone resistance and intermediate resistance to azithromycin, Ireland, August 2018. Eurosurveillance. 2018;23(47):1-4. doi:10.2807/1560-7917.ES.2018.23.47.1800617.

Return to footnote 28 referrer

Footnote 29

Eyre DW, Sanderson ND, Lord E, Regisford-Reimmer N, Chau K, Barker L, et al. Gonorrhoea treatment failure caused by a Neisseria gonorrhoeae strain with combined ceftriaxone and high-level azithromycin resistance, England, February 2018. Euro Surveill. 2018;23(27):pii=1800323. doi:10.2807/1560-7917.ES.2018.23.27.

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Footnote 30

Sherrard J, Barlow D. Gonorrhoea in men: clinical and diagnostic aspects. Genitourin Med. 1996;72(6):422-426.

Return to footnote 30 referrer

Footnote 31

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

Return to footnote 31 referrer

Footnote 32

Schachter J, McCormack WM, Chernesky MA, et al. Vaginal swabs are appropriate specimens for diagnosis of genital tract infection with Chlamydia trachomatis. J Clin Microbiol. 2003;41(8):3784-3789.

Return to footnote 32 referrer

Footnote 33

Manavi K, Young H. The significance of voiding interval before testing urine samples for Chlamydia trachomatis in men. Sex Transm Infect. 2006;82(1):34-36.

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Footnote 34

Mathew T, O'Mahony C, Mallinson H. Shortening the voiding interval for men having chlamydia nucleic acid amplification tests. Int J STD AIDS. 2009;20(11):752-753.

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Footnote 35

McCormack WM, Stumacher RJ, Johnson K, Donner A. Clinical spectrum of gonococcal infection in women. Lancet. 1977;1(8023):1182-1185.

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Footnote 36

Chan PA, Robinette A, Montgomery M, et al. Extragenital Infections Caused by Chlamydia trachomatis and Neisseria gonorrhoeae: A Review of the Literature. Infect Dis Obstet Gynecol. 2016;2016:5758387. doi:10.1155/2016/5758387

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Footnote 37

Jin F, Prestage GP, Zablotska I, et al. High rates of sexually transmitted infections in HIV positive homosexual men: data from two community based cohorts. Sex Transm Infect. 2007; 83(5):397-399.

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Footnote 38

Dukers-Muijrers NH, Schachter J, van Liere GA, Wolffs PF, Hoebe CJ. What is needed to guide testing for anorectal and pharyngeal Chlamydia trachomatis and Neisseria gonorrhoeae in women and men? Evidence and opinion. BMC Infect Dis. 2015;15:533. Published 2015 Nov 17. doi:10.1186/s12879-015-1280-6

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Date modified:: 2024-12-23

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