Chlamydia trachomatis – Culture

Specimen Collection and Handling

Specimen Requirements

Test Requested Required Requisition(s) Specimen Type Minimum Volume Collection Kit

Chlamydia trachomatis / CT culture

Genital, non-genital swabs (rectal, throat/ pharyngeal, conjunctival scrapings/swabs)

1.0 mL of fluid

PHO CHL(C) kit / Chlamydia trachomatis culture kit order # 390083 or 390084 or a universal transport medium (UTM) for swabs or a sterile container for fluids/tissue.

Chlamydia trachomatis / CT culture

Tissue

Available tissue

PHO CHL(C) kit / Chlamydia trachomatis culture kit order # 390083 or 390084 or a universal transport medium (UTM) for swabs or a sterile container for fluids/tissue.

Chlamydia trachomatis / CT culture

Neonatal – fluid from auger suction, transtracheal / nasopharyngeal aspirates, conjunctival swabs

1.0 mL of fluid

PHO CHL(C) kit / Chlamydia trachomatis culture kit order # 390083 or 390084 or a universal transport medium (UTM) for swabs or a sterile container for fluids/tissue.

Chlamydia trachomatis / CT culture

Sexual abuse and/or sexual assault cases in peri-pubertal and pre-pubertal children, including rectal, throat/pharyngeal, vaginal, and urethral swabs

1.0 mL of fluid

PHO CHL(C) kit / Chlamydia trachomatis culture kit order # 390083 or 390084 or a universal transport medium (UTM) for swabs or a sterile container for fluids/tissue.

Submission and Collection Notes

1

Unsuitable specimens: Urine and seminal fluid are not acceptable specimen sites for Chlamydia trachomatis culture. Dry swabs and swabs in bacteriological transport media (gel) are not acceptable collection kits for Chlamydia trachomatis culture and testing will not be performed.

2

Do not use expired kits.

3

Follow the collection instructions in the Chlamydia trachomatis culture – Male or Female Kit Instruction Sheet.

Preparation Prior to Transport

Label the specimen container with the patient’s full name, date of collection, and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.

Special Instructions

Specimens should be stored at 2-8°C after collection and shipped on ice. Transport to the laboratory as soon as possible.

Specimens should be received at the testing laboratory within 48 hours of collection; this is especially important for neonatal and paediatric specimens. In situations of delayed transportation, specimens should be frozen at -70°C and transported on dry ice. Do not freeze sample at -20°C.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Chlamydia trachomatis specimens are tested 3 times per week.

Turnaround time is up to 7 days from receipt by PHO laboratory.

Reporting

Results are reported to the ordering physician or health care provider as indicated on the requisition.

Critical positive reports (results from body fluids/aspirates, tissues, CSF or specimens from pregnant patients, infants, pre-pubertal children, i.e. ≤ 12 years and medico-legal specimens, i.e. pre-pubertal children, sexual abuse in peri-pubertal and pre-pubertal children, sexual assault and legal cases) are phoned and faxed if the client is registered for auto fax. 

Other positives are only faxed if client is registered for auto fax.

Specimens that are positive for Chlamydia trachomatis are reported to the Medical Officer of Health as per the Health Protection and Promotion Act.  

Test Methods

Specimens are tested using standard cell culture technique.

Interpretation

Results may be interpreted as positive, negative or toxic. 

Toxicity may occur for various reasons including antibiotic therapy or high specimen pH and retesting may be required.

Data and Analysis

Additional Information

Medico-legal specimens

Culture is the specimen of choice for all potentially medico-legal specimens, i.e. pre-pubertal children, sexual abuse in peri-pubertal and pre-pubertal children, sexual assault and legal cases. Legal specimens should be transported to the laboratory under legal seal; contact the Medical Microbiologist prior to specimen collection.

Test of Cure (TOC)

General guidelines for Chlamydia trachomatis (CT) Test of Cure (TOC) are described below. Refer to the PHAC Canadian Guidelines on Sexually Transmitted Infections for detailed information.

TOC by NAAT is recommended 3-4 weeks after completion of treatment when compliance to treatment is suboptimal, an alternative treatment regimen is used, for those with persisting signs or symptoms post-treatment, or the individual is prepubertal or pregnant.

For Lymphogranuloma venereum (LGV), TOC is recommended 3 weeks after completion of treatment. Follow LGV-infected individuals until CT is negative and symptoms have resolved.

In rare circumstances, CT DNA may persist for longer than 4 weeks and therefore must be considered when interpreting positive TOC results. Repeat screening is recommended 3 months post-treatment for all individuals with CT infection.

LGV testing

Male rectal specimens positive for Chlamydia trachomatis will be routinely forwarded to the National Microbiology Laboratory (NML) in Winnipeg for Lymphogranuloma venereum (LGV) testing.  Specimens positive for Chlamydia trachomatis from other sources will only be sent if LGV testing is specifically requested.

contact lab

Contact Laboratory Customer Service

Laboratory Services

customerservicecentre@oahpp.ca

Updated 20 July 2020