Chlamydia testing (including urine tests)

Question

I recently had a Chlaymidia urine test (PCR-DNA) performed approximately one week after the possible exposure. The test came back negative. I have a couple questions regarding my test:

  1. Is the PCR-DNA test a fairly accurate test?
  2. Was my window period long enough?
  3. I have read on the internet that you should take the test in the morning (after 3-4 hours without urinating). I had the test performed around noon-time, and after ~1 hr from my last urination. Does this really matter?
  4. My only "symptom" is that my urethra is a little irritated/sensitive. It does not burn when I urinate, and I don't seem to have any unusual discharges. Could it be possible that the urethra is just irritated from excess self-examination?

Thank you doctor for you input regarding these matters.

Answer

Thank you for your question.

When we are doing tests for chlamydia, there are different types of tests available (cell culture, Direct Fluorescent Antibody, EIA, Nucleic Acid Probe, LCR, PCR, and TMA-CT). Some of the newer tests available can use both swab specimens and also urine specimens (for example LCR, PCR, and TMA-CT tests). As you can imagine, urine specimens are a lot easier (as less painful) to collect from people. Generally speaking, these tests will often detect an infection by the first week after infection. When urine is being used for these tests there should preferably be no urination one hour prior to collection, and only the first 15-20 ml of urine are collected in the specimen container. Tests results often come back in a day or so (depending on the test). Like any other laboratory test, each of these tests have their limitations, and not every test can be used in all situations.

If you tested negative on a urine PCR test after 1 week, there is a good chance that you do not have chlamydia. However, you will need to talk to your doctor to determine the cause of any symptoms you are having. There are other medical problems that may be causing your symptoms (which may require you to take additional laboratory tests).

If you have any further questions, please feel free to call the Centers for Disease Control at 1.800.232.4636 (Nationwide).