STI SCREENING

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The type of tests required to screen individuals for STI depends on the sexual history and risk behviour of the individual. The risk of a patient having a particular STI depends on the type of sexual behaviour that has occurred (such as unprotected anal or vaginal intercourse) and the likelihood of their partner or partners having an STI. The latter is increased if for example the partner is from a country where STI are more prevalent or is from a group where STI are more prevalent – such as men who have sex with men and remote Aboriginal and Torres Strait Islander communities. 

Guidelines for screening tests in asymptomatic individuals are detailed in the table below. For screening of sex workers please refer to the MSHC guideline on sex workers.

Patient

Which STI?

Specimen

Laboratory Method

Low risk heterosexual women (1) (2)

 

Chlamydia

 

FPU or

endocervical or vaginal swab

NAAT for chlamydia

Higher risk heterosexual women with a risk factor such as overseas sexual contact or IDU
(1) (2) (3) (4) (5)

 

Chlamydia

FPU or

endocervical swab OR vaginal swab

NAAT for chlamydia

Gonorrhoea

FPU or

endocervical swab or vaginal swab

NAAT for gonorrhoea

Trichomonas

Vaginal swab

NAAT for trichomonas

Hepatitis B Syphilis  HIV Hepatitis C (4)

Serology

Hepatitis B core and surface antibodies Syphilis antibodies HIV antibodies Hepatitis C antibodies

Low risk heterosexual men (1) (2)

Chlamydia

 FPU

 NAAT for chlamydia

Higher risk heterosexual men with other risk factors such as overseas sexual contact or IDU (1) (2) (3) (4)

Chlamydia

FPU

NAAT for chlamydia

Hepatitis B Syphilis HIV Hepatitis C (4)

Serology

Hepatitis B core and surface antibodies
Syphilis antibodies
HIV antibodies
Hepatitis C antibodies

Men who have Sex with Men (MSM)

(3) (5) (6) (7) (8)

For more detailed information see:
www.stipu.nsw.gov.au/STIGMA_Testing_Guidelines_Final_v5.pdf

Chlamydia

FPU and

Anal swab
Pharyngeal swab

NAAT for chlamydia

NAAT for chlamydia
NAAT for chlamydia

Gonorrhoea


Anal swab
Pharyngeal swab

NAAT for gonorrhoea

Hepatitis A Hepatitis B Syphilis HIV

Serology

Hepatitis A antibody
Hepatitis B core and surface antibodies
Syphilis antibodies
HIV antibodies

MSM Contact of gono

Chlamydia



Gonorrhoea

FPU
Ano-rectal swab
Pharyngeal swab

FPU

Ano-rectal swab

Pharyngeal swab

NAAT for chlamydia
NAAT for chlamydia
NAAT for chlamydia

NAAT for gonorrhoea

NAAT for gonorrhoea

NAAT for gonorrhoea


Heterosexual male contact of gonorrhea (in female partner)


Chlamydia
Gonorrhoea

FPU
FPU

NAAT for chlamydia
NAAT for gonorrhoea

Female contact of gonorrhoea in male partner

Chlamydia

FPU or vaginal swab

NAAT for chlamydia

Gonorrhoea

FPU or vaginal swab

NAAT for chlamydia
Culture for gonorrhoea

Gonorrhoea

Pharyngeal swab

NAAT for chlamydia
Culture for gonorrhoea

MSM with a positive NAAT test for gono at any site (before treatment)


Gonorrhoea culture only (before treatment)


Ano-rectal swab pharyngeal or urethral swab depending on site of infection


Culture for gonorrhoea
Culture for gonorrhoea

Culture for gonorrhoea

(before treatment as NAAT already positive)

FPU= First Pass Urine
NAAT=Nucleic Acid Amplification Test (this includes PCR = polymerase chain reaction)
IDU: injecting drug use

Notes:

  1. Gonorrhoea has a very low prevalence among heterosexuals in Australian cities. There is a higher prevalence in many other countries including developed countries such as USA and UK and in parts of Australia where access to services is poor such as remote areas. There is a high prevalence of gonorrhoea among men who have sex with men.
  2. Whether HIV testing is indicated in heterosexual females and males depends on the sexual history and risk. The risk for HIV in heterosexuals in Australia is much lower than for men who have sex with men but the tests should be done if there are any specific risks, e.g. sex in high prevalence country, sex with a partner at risk of HIV, IDU or if the patient requests HIV testing.
  3. Men who report sex with men and anyone with overseas sexual contact or a history of IDU and no history of vaccination should be offered Hepatitis B screening.
  4.  Hepatitis C should be included with a history of IDU or by patient request. HIV positive men who have sex with men should also be screened for hepatitis C as in this population sexual transmission of hepatitis C can occur.
  5. Urethral gonorrhoea is usually symptomatic so gonorrhoea screening of the urethra in men with no urethral symptoms is not necessary. In contrast, gonorrhoea in the pharynx and rectum is usually asymptomatic. NAATs have a higher sensitivity than culture for diagnosing gonorrhoea. The specificity of these NAAT tests is better in populations with a high prevalence of gonorrhoea such as men who have sex with men but is lower where the prevalence of gonorrhoea is lower. False positive results can occur and should be suspected if gonorrhoea NAAT is positive in an individual who is low risk for STI. If a NAAT is positive for gonorrhoea a test for culture is advisable before treatment. This is to monitor the MIC (minimum inhibitory concentration) as resistance of gonorrhoea to antibiotics is increasing worldwide.
  6. Anal swabs for chlamydia and gonorrhoea should be offered to all men who have sex with men even if they do not report receptive anal intercourse.
  7. Men reporting sex with men should be screened for the STIs listed in the table above at least once a year with more frequent screening (3-6 monthly) for those at increased risk such as those with higher numbers of casual partners e.g. >10 partners in the past year. Infectious syphilis is commonly asymptomatic so syphilis screening should be included as part of this. HIV positive men who have sex with men should have syphilis screening as part of the regular, routine tests that are done for HIV monitoring. An HIV test should also be included in the screening of HIV negative men who have sex with men even if men do not report unprotected anal sex.
  8. Hepatitis A can be sexually transmitted. Vaccination for Hepatitis A and B should be offered to all men who have sex with men who are not immune to hepatitis A and B.
  9. Positive HIV results must not be given over the telephone: a client with a positive HIV result who needs to be recalled should be asked to attend for the result to be given
  10. Individuals who screen positive for gonorrhoea by NAAT and who have not been treated for gonorrhoea should be recalled for treatment. On the day of treatment culture should be taken from the gonorrhoea NAAT positive site (pharynx, rectum and/or cervix) for sensitivity. A gonorrhoea test of cure is only needed 7 days later if the culture on the day of treatment is positive. If culture is negative TOC is not needed.

Disclaimer
The content of these treatment guidelines is for information purposes only. The treatment guidelines are generic in character and should be applied to individuals only as deemed appropriate by the treating practitioner on a case by case basis. Alfred Health, through MSHC, does not accept liability to any person for the information or advice (or the use of such information or advice) which is provided through these treatment guidelines. The information contained within these treatment guidelines is provided on the basis that all persons accessing the treatment guidelines undertake responsibility for assessing the relevance and accuracy of the content and its suitability for a particular patient. Responsible use of these guidelines requires that the prescriber is familiar with contraindications and precautions relevant to the various pharmaceutical agents recommended herein.

Last Updated: January 2017