Applicants preparing for their I-693 exam often assume the required syphilis and gonorrhea screening is a single test, or at least a single needle stick. It isn’t. The two conditions are grouped together on the exam checklist because both are sexually transmitted infections USCIS classifies as communicable diseases of public health significance, but the laboratory work behind them is genuinely different — different specimen, different technology, and in syphilis’s case, a two-step confirmation process rather than a single result.
Why Two Different Diseases Get Two Different Tests
Syphilis and gonorrhea are caused by entirely different organisms — a spirochete bacterium for syphilis, a different bacterium for gonorrhea — and they behave differently in the body. Syphilis produces detectable antibodies in the bloodstream, which is why it lends itself to serology (blood-based antibody testing). Gonorrhea is a localized infection that a modern molecular test can detect directly from genital or urine specimens without needing a blood draw at all. A civil surgeon isn’t choosing between methods arbitrarily; each test is built around how that particular organism actually shows up in a sample.
Syphilis: A Blood Draw, Then a Second Test to Confirm
Syphilis screening on the I-693 uses a blood sample, and it typically involves two categories of laboratory test rather than one:
- Nontreponemal tests — the Venereal Disease Research Laboratory (VDRL) test or Rapid Plasma Reagin (RPR) — are the initial screen. These look for antibodies the body produces in response to tissue damage from infection, not for the syphilis organism itself, which is why a reactive result is followed by a quantitative titer rather than treated as a final answer on its own.
- Treponemal tests confirm that a reactive nontreponemal result is actually syphilis and not a false positive from something unrelated. Depending on the lab, this confirmatory step may use T. pallidum passive particle agglutination (TP-PA), Treponema pallidum hemagglutination (TPHA), enzyme immunoassays, chemiluminescence immunoassays, fluorescent treponemal antibody absorption (FTA-ABS), or immunoblot testing.
Both stages run on the same blood draw, so applicants don’t need a second appointment for the confirmatory step — but it does mean a single vial of blood is doing more laboratory work than most applicants expect.
Gonorrhea: A Urine Sample or Swab, Not a Blood Test
Gonorrhea screening works on a completely different principle. The method used is a Nucleic Acid Amplification Test (NAAT), which detects the genetic material of the gonorrhea-causing bacteria directly, rather than looking for antibodies. Because NAAT doesn’t rely on the bloodstream at all, the specimen is not a blood draw:
- A urine sample is the standard, least invasive collection method for both men and women.
- A self-collected vaginal swab is an accepted alternative for women.
- Oral or rectal swabs may be used when specific risk factors or symptoms point to infection at those sites.
This is the detail that surprises a lot of applicants who read "STI screening" and picture one blood test covering everything. In practice, a single I-693 appointment usually involves one blood draw (which also covers syphilis and, separately, any required titer or vaccine-related bloodwork) and a separate urine or swab specimen collected specifically for gonorrhea.
Side by Side: What Each Test Actually Involves
| Screening | Specimen Type | Test Method | Result Handling |
|---|---|---|---|
| Syphilis | Blood draw | Nontreponemal screen (VDRL/RPR), confirmed by a treponemal test if reactive | Reactive results are reported with a quantitative titer |
| Gonorrhea | Urine (standard) or vaginal/oral/rectal swab | Nucleic Acid Amplification Test (NAAT) | Detects bacterial genetic material directly |
Why Results From Elsewhere Won’t Count
One rule trips up applicants who assume they can save time or money by bringing in recent lab work from their own doctor: syphilis and gonorrhea testing for the I-693 has to be ordered by the civil surgeon at the time of the immigration medical examination itself. Testing performed at an outside clinic, an urgent care visit, or even a recent physical with the applicant’s regular physician is not acceptable as a substitute, regardless of how recent or how negative the results were. The civil surgeon needs to control the chain of custody on these specimens from collection through to the lab report that gets summarized on Form I-693, and that only works if the sample was drawn under the exam itself.
Practically, that means there’s no way to shorten the appointment by pre-testing. What an applicant can do is arrive prepared: know that a blood draw is coming for the syphilis screen, that a urine sample (or, for some applicants, a swab) will be collected separately for gonorrhea, and that a reactive syphilis screen doesn’t mean a final diagnosis until the confirmatory treponemal test comes back. Understanding the mechanics ahead of time turns what can feel like an intrusive, confusing part of the exam into a predictable, two-specimen process with a clear reason behind each step.
The Takeaway
Syphilis and gonorrhea screening on the I-693 aren’t one test wearing two names — they’re built on different biology, collected with different specimens, and read with different laboratory methods. Syphilis relies on a blood draw and a two-stage antibody confirmation process; gonorrhea relies on a NAAT run on urine or a swab. Both have to happen at the civil surgeon’s office, on the day of the exam, for the results to count toward Form I-693.