“My recent urine test is Negative so I am free of STDs”
The sad truth is that this statement is inaccurate and has led to many misunderstandings.
This is because there are a whole range of urine tests available each for its own specific purpose. Not every urine test is able or meant to detect an STD.
Getting the right urine test done at the right time ensures maximum accuracy in screening for STDs. Allowing you to detect an infection early, get prompt treatment and avoid any unnecessary complications.
Urine is produced by your kidneys which act as your body’s filter to clear away any excess salts or toxins and keep the good stuff like proteins. From the kidneys, the urine flows down into the bladder where it is stored until it is ready to get released through the urethra. Urine is an important sample to obtain to help doctors detect if there is something amiss and depending on how the urine is collected and what it is tested for, doctors can pin-point where the problem is.
What is the difference between a first catch and mid-stream urine sample?
Collection method matters!
When you come for your urine test, the clinic will give you specific instructions for collecting the urine.
First Catch Urine
If you are testing for an STD, you will be told to hold your urine for at least 30 minutes and to provide the first part of your urine. This is because most STDs tend to reside at the end of the urethra (the urinary tube inside the penis). Therefore holding your urine and giving the first part of the urine allows the most amount of STD organisms to be flushed into the sample bottle.
So if this method of urine collection is news to you, you may not have been testing for STDs in your urine!
Mid-Stream Urine
This leads us to the second and most common method of urine collection – a mid-stream urine sample. As the name suggests, for this sample, the clinic will ask you to urinate for approximately 3 seconds before filling the sample bottle. This is a very different method of urine collection and is used to detect elements that are not supposed to be in the urine such as
- Blood
- Protein
- By-products of kidney stones
- Non-STD bacteria
Different testing methods
A stick, a microscope or a plate. The way your urine is processed also provides different information for your doctor.
Urine Dipstick
A dipstick is something many are familiar with, and while it does give good basic information if there are any contaminants in your urine it is not specific for STDs.
Urine Microscopic Examination
A microscope is used in some situations (in a test called the UFEME) and allows for the detection of any red blood cells/ white blood cells, bacteria or crystals in your urine. This test like the dipstick is also a preliminary test to detect abnormalities but cannot confirm the presence of an STD. I have come across instances where a patient tested positive for an STD but had a normal UFEME.
Urine Bacterial Culture
A culture plate is the next common method of urine analysis. Urine is applied onto culture medium to encourage any bacteria in the urine to grow. This is appropriate for common UTI causing bacteria (Non-STD bacteria) but because most STD organisms are fragile, they do not grow well on the culture plate. Therefore a negative urine culture does NOT always mean you are negative for STDs.
PCR as the Gold Standard
The polymerase chain reaction, or PCR test is the Gold Standard for detecting STDs such as Chlamydia and Gonorrhea. In this test, genetic material from the STD organisms are picked up and amplified. This means that even fragmented STD organisms can be detected by this method thus making it better at detecting an STD than a culture plate.
Interpreting your Urine Test
Doctors differ in their definitions when they say they are testing you for “everything”. You first clue as to whether or not you are being screened for STDs is whether the Doctor asked you for a first catch sample or a mid-stream sample (as discussed above).
When you get your report look for:
- What organism was tested for
- What testing technique was used
- What the outcome was
Here is another example:
- What organism was tested for – General Culture (multiple organism can grow)
- What testing technique was used – Culture
- What the outcome was – Group B Streptococcus Positive
In this other example you can see:
- What organism was tested for – Ureaplasma and Mycoplasma
- What testing technique was used – Culture
- What the outcome was – Ureaplasma Positive
Not only in the urine
STD infections are site-specific. In other words, not detecting an STD in the urine does not mean it cannot be found elsewhere. This can lead to serious misunderstandings.
A common scenario I encounter is this. First I see a patient whom I diagnosed and treated for a Gonorrhea infection in his penis. He has been with only one partner and I counsel him to advice his partner to get tested and treated. He dutifully does so then sees me a week later completely flustered. His partner tested negative for Gonorrhea and is now blaming him! So I ask – did your partner only test her urine? Did her Doctor also test her throat? Invariable the answer is – only urine test done, no throat swab done. And she goes back to her Doctor to get a throat swab and the swab indeed tests positive for Gonorrhea.
The lesson here is this – STD infections are site specific. Depending on sexual practices, more than one site may need to be screened. Common sites that require screening are – Urethra, Vagina, Throat and Rectum.
In the above report, pay attention to the source. This is an anal swab which shows a Chlamydia infection.
In Conclusion
Unless specified, the majority of the health screens in Singapore will NOT test for an STD in your urine. The focus is mostly geared towards chronic ailments such as diabetes, kidney stones and cancer. So you do need to request for one when you are attending a health screen.
Your urine sample can be analysed many different ways and not all methods are meant to detect an STD. Therefore, it is important that you speak to your doctor and request for an STD specific urine test.
Have a question? Please put it in the comments section below.
Or visit us at our Men’s Health Clinic.
Sorry for off topic but comments were closed on other post. I had an HIV RNA test at 14 days post exposure. My results were negative. P24 was also negative. Can I be confident in this test?
Hi Tony. According to the US CDC Updated Guidelines on the Lab Diagnosis of HIV, the HIV RNA test detects a HIV infection as early as D8 and definitely by D10. So I would be extremely confident in your test results.
https://drtanmenshealthblog.com/2021/04/12/how-accurate-are-hiv-tests/#HIV_Testing_Window_Period