Vaginal swabs are the best way to detect STIs

Vaginal swabs are more effective than urine tests when checking for the certain sexually transmitted infections (STIs).

Maria Zavialova

According to recent research, vaginal swabs have shown to be marginally more precise than urine tests when it comes to identifying certain sexually transmitted infections (STIs) in women. Specifically, this refers to STIs such as chlamydia, trichomoniasis, and gonorrhea.

The cause for the study

The aforementioned illnesses are some of the most prevalent sexually transmitted infections (STIs). In 2020, chlamydia was diagnosed in 129 million individuals globally, while trichomoniasis and gonorrhea were diagnosed in 156 million and 86 million people, respectively.

Early diagnosis of these infections is crucial for effective and timely treatment. This can help prevent complications and further spread of these diseases.

To this end, researchers from the University of Alabama at Birmingham (UAB) recently conducted an analysis to determine the most effective method for testing for STIs. Although vaginal swabs are the recommended approach, urine samples are often used as a substitute.

Vaginal swabs are more accurate than urine samples

The researchers conducted a systematic search of multiple databases and identified 28 eligible articles. Among them, 30 comparisons for chlamydia, 16 comparisons for gonorrhea and nine comparisons for trichomoniasis. They found that the pooled sensitivity estimates for vaginal swabs were higher than those for urine specimens. Specifically, the sensitivity estimates for vaginal swabs and urine, respectively, were 94.1 percent and 86.9 percent for chlamydia, 96.5 percent and 90.7 percent for gonorrhea, and 98.0 percent and 95.1 percent for trichomoniasis.

The STIs examined in the study are usually not detectable in the urethra. They only show up in urine tests if cervical or vaginal cells are present in the urine sample.

The conclusions drawn by the scientists

We hope the evidence presented in our article encourages health care providers to use the latest CDC STI testing and treatment guidelines in their clinical decision-making. Evidence from our review supports the genital sample type recommended by the CDC in women for the laboratory testing of chlamydia and gonorrhea.

Lead author Kristal Aaron

Kristal Aaron, PhD and clinical data manager at UAB, emphasizes that using urine for testing can lead to false negative results. This means untreated infections, the spread of diseases, and higher risk of complications for women, including infertility. That’s why vaginal swabs should be the recommended method for testing.

Of course, vaginal swabs are more invasive, so women often prefer urine testing. However, the risks of untreated sexually transmitted infections far outweigh the discomfort.

The conclusions were published in the scientific journal “Annals of Family Medicine“.

Our next steps include further investigation of additional articles in which both urine and vaginal swabs were used for Trichomonas vaginalis testing. We need to conclude definitively which sample type works best for TV testing in women (since it was not statistically significant in our metanalysis). We also want to continue research into best practices for STI diagnostics.

Lead author Kristal Aaron

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