Does Improper Urine Sample Collection Affect STD Test Results?

Urine sampling issues?

Hello, doctor.
A few days ago, I went to a testing center in central Taiwan for a full sexually transmitted infection screening.
Although the results came back negative, I later learned that a midstream urine sample should be collected.
I collected the urine directly instead.
Will this affect the results, and do I need to retest? The testing is quite expensive, so I wanted to ask about this.
Thank you!

Nín hǎo, 30~39 year old female. Ask Date: 2017/11/22

Dr. Liao Yaopan reply Family Medicine

To avoid contamination, a midstream urine sample will be collected for routine urinalysis.
In the situations mentioned above, it is advisable to consult with the testing facility for further confirmation.
Reminder: Online consultations do not equate to in-person medical visits and cannot provide accurate diagnoses or treatment recommendations.
Changhua Hospital cares about you.

Reply Date: 2017/11/22

More Info

Improper urine sample collection can indeed affect the results of STD tests, particularly those that rely on urine samples for detection, such as tests for chlamydia and gonorrhea. The standard practice for collecting urine samples for these tests is to use a "midstream" collection method. This means that the first part of the urine stream is not collected, but rather, the sample is taken after the initial flow has started. This method is recommended because the initial urine can contain contaminants from the urethra, which may lead to false-positive or false-negative results.

When you collect urine without following the midstream method, you may inadvertently include bacteria or other substances that are not representative of the infection status in the bladder or urethra. This can lead to inaccurate test results. For instance, if you have a mild infection, the initial flow may wash away some of the pathogens, resulting in a negative test when the infection is actually present. Conversely, if there are contaminants in the initial flow, it could lead to a false positive.

In your case, since you mentioned that you collected the urine sample directly without following the midstream method, it is advisable to consider retesting. Although your initial results came back negative, the accuracy of those results could be compromised due to the improper collection technique. Given the importance of accurately diagnosing STDs, especially if you have had potential exposure, it would be prudent to discuss your concerns with your healthcare provider. They may recommend a repeat test using the correct collection method to ensure that the results are reliable.

Additionally, if you are experiencing any symptoms or have concerns about potential exposure to STDs, it is essential to communicate this with your healthcare provider. They may suggest additional tests or examinations based on your individual risk factors and health history.

In summary, while your initial test results were negative, the method of urine collection could potentially impact the accuracy of those results. It is recommended to retest using the midstream collection method to ensure that you have a definitive answer regarding your STD status. Always prioritize open communication with your healthcare provider to address any concerns and ensure appropriate follow-up care.

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