Throat/Anus Chlamydia (PCR)

Chlamydia trachomatis is the most common mandatory reporting STD (STI) in Quebec. It is often asymptomatic and, if left untreated, can lead to complications affecting the genital organs and infertility. The screening technique (PCR or NAAT) detects the bacteria’s DNA or RNA (genetic material) after amplification. Results are generally positive about 2 weeks after infection. Depending on the risk factors, chlamydia testing can be performed on a urine, genital, urethral, throat or anal sample. A warning on the report indicates that the technique used was not approved by Health Canada for throat or anal specimens. However, these tests are done at the Laboratoire de Santé publique du Québec (LSPQ) and are very reliable.

A positive (reactive) result indicates the presence of an active bacterial infection. A negative (non-reactive) result only indicates the probable absence of infection at the time of sample collection. Higher-risk individuals should be regularly retested for infection or reinfection. Some samples produce results that are more difficult to interpret. These results are identified as “ambiguous,” “inhibition,” “uninterpretable” or “indeterminate.” The test must then be repeated on a new sample.