Several common STDs can infect different parts of your body depending on how you were exposed to them, and getting the wrong test could miss this!
For example, having unprotected vaginal sex could lead to a genital chlamydia infection. But having unprotected oral sex could lead to oral chlamydia. A urine test would miss the oral infection, and an oral swab could miss the genital infection. Both can cause you health complications, and both can be passed to new partners. As a result, depending on your practices, we often recommend both urine and oral swab tests.
In our experience, poorly understanding how your sexual practices inform your real testing needs is one of the biggest challenges individuals face when seeing a doctor for their testing needs.