Chlamydia is one of the most commonly reported sexually transmitted diseases in the United States. The CDC estimates approximately 4 million new cases per year. Several methods are often used to test for chlamydial infection. The most common method is the use of the DNA probe–a test similar to a Pap smear. This test has a sensitivity of 65% to 70 % meaning that 65% to 70% of people who test positive truly have the disease. It has a specificity of 95% to 99% meaning the 95% to 99% of people who test negative truly do not have the disease.

If you tested negative for chlamydia by DNA probe, it is unlikely that you had chlamydia at the time of test. If later you had a positive test, it would be most likely that you acquired chlamydia during that time frame. It is possible to harbor chlamydia in the tissues for a long period of time, and therefore it is possible that your sexual partner may have had the infection and just recently passed it on to you. To date, there does not appear to be a significant incubation period for chlamydia. It is a sexually transmitted disease.