Chlamydia is one of the most frequently reported bacterial sexually transmitted infections, caused by the organism Chlamydia trachomatis. Receiving a positive test result while a current sexual partner tests negative can be confusing and distressing. This discrepancy is common and stems from several biological and diagnostic factors. Understanding the nuances of this infection is the first step toward effective treatment and preventing future transmission.
Why Chlamydia Often Goes Unnoticed
The primary reason for differing results between sexual partners is the high rate of asymptomatic infection. Chlamydia trachomatis often colonizes the body’s mucous membranes without causing noticeable symptoms. In women, approximately 70% to 80% of urogenital chlamydia infections present with no symptoms. Men also frequently experience a lack of physical manifestation, with about 50% of infections being asymptomatic.
An infected person can carry and transmit the bacterium for months or years without realizing it, delaying diagnosis. When symptoms do occur, they are often mild and easily dismissed, sometimes resembling a urinary tract infection. Subtle signs may include a slight watery or mucoid discharge, mild pain during urination, or unusual spotting between menstrual cycles. The absence of feeling sick does not indicate the absence of the infection or the inability to pass it to others.
Factors Affecting Test Accuracy and Timing
A negative result in a partner does not definitively mean they are uninfected; it may simply mean the test was conducted too early. Chlamydia testing relies on detecting the bacterium’s genetic material using Nucleic Acid Amplification Tests (NAATs), which are highly sensitive. However, the infection must first multiply enough to reach a detectable level, a period known as the “window period.” For chlamydia, this period ranges from five to 21 days after exposure.
If a partner was tested shortly after potential exposure, a false negative result is possible because the bacterial load was too low for the test to register. Retesting after the recommended window has passed is necessary to confirm a negative status.
The type of sample collected is another factor influencing accuracy. While a urine sample is commonly used for screening, the infection can be present at multiple sites, including the rectum and pharynx, depending on the types of sexual contact. If exposure included these sites, but only a urine test was performed, a site-specific infection could be missed.
Navigating Exposure, Infection, and Source
Exposure to the bacterium does not automatically guarantee infection. The transmission probability of C. trachomatis per single sexual act is not 100%, with estimates ranging from 4.5% to 40%. Biological factors, such as the individual immune response, influence whether the bacterium successfully colonizes and establishes an infection.
The infection timeline also varies greatly between individuals. In some cases, the bacterium may spontaneously clear from the body without treatment; this is more common in women within a year. Your positive result may reflect a recent acquisition, while your partner may have been exposed but successfully cleared the infection.
One partner may have been carrying an asymptomatic infection for a long time, only recently transmitting it to the other. Tracing the exact source and time of infection is often difficult and rarely productive. The focus should shift from determining the source to ensuring both partners are treated promptly to prevent long-term health complications and re-infection.
Treatment and Partner Communication
Treatment for chlamydia involves a course of antibiotics, such as a single dose of azithromycin or a seven-day regimen of doxycycline. Prompt treatment is necessary to avoid serious health issues, including pelvic inflammatory disease in women. Both partners must be treated simultaneously, even if one tested negative, especially if they were tested within the window period.
Healthcare providers often recommend Expedited Partner Therapy (EPT). EPT allows the diagnosed patient to take medication or a prescription to their current partner without a separate medical exam. This strategy is effective in reducing the risk of treatment failure and re-infection.
After completing treatment, couples must abstain from sexual contact for seven days, or until the entire course of antibiotics is finished and all symptoms have resolved. Open and non-judgmental communication is the most important step after diagnosis. Framing the conversation around shared health and the need for dual treatment, regardless of test results, is the most constructive approach. Consulting a healthcare professional for guidance on partner notification and follow-up testing is recommended to ensure complete resolution of the infection.