STI PCR testing in Chiang Mai: 14- and 28-target panels
A practical guide to panel contents, genital and extragenital specimens, what the results can—and cannot—tell you, and how a doctor selects the appropriate test.
What is an STI PCR panel?
A multiplex PCR panel looks for genetic material from several organisms in one specimen. Klaibaan Clinic can arrange a 14-target panel, individual 7-target modules from the 28-target system, or the full 28-target option. The largest panel is not automatically the best choice: the doctor should match the panel and specimen to symptoms, exposure site, timing, and other tests you may need.
When molecular testing may be considered
- Discharge, burning urination, genital discomfort, sores, pelvic symptoms, or rectal symptoms
- Possible genital, oral, or anal exposure to an STI
- A partner diagnosed with an infection
- Persistent or recurrent symptoms when a focused molecular panel may clarify the cause
- Testing requested after clinical assessment even when symptoms are absent
Panel overview
The 14- and 28-target options overlap, but one is not a strict superset of the other.
| 14-target panel | A mixed panel covering common bacterial, viral, parasitic and fungal targets, including Group B Streptococcus. |
|---|---|
| Essential STI panel | 7 targets focused on common urogenital organisms. |
| Genital Ulcer panel | 7 viral and bacterial targets associated with genital ulcers. |
| Candidiasis panel | 7 Candida species. |
| Bacterial Vaginosis panel | 7 BV-associated or vaginal-microbiome targets. |
| Full 28-target option | Combines all four 7-target modules. It does not include Group B Streptococcus from the 14-target panel. |
What is included in the 14-target panel?
This panel includes ten bacterial targets, two viral targets, one parasite, and one fungal target.
- Chlamydia trachomatis
- Gardnerella vaginalis
- Mycoplasma genitalium
- Mycoplasma hominis
- Neisseria gonorrhoeae
- Treponema pallidum
- Ureaplasma urealyticum
- Ureaplasma parvum
- Group B Streptococcus
- Haemophilus ducreyi
- Herpes simplex virus 1
- Herpes simplex virus 2
- Trichomonas vaginalis
- Candida albicans
What is included in the 28-target system?
Each module contains seven targets and may be ordered individually when appropriate.
Essential STI
- C. trachomatis
- N. gonorrhoeae
- M. genitalium
- M. hominis
- T. vaginalis
- U. urealyticum
- U. parvum
Genital Ulcer
- HSV-1
- HSV-2
- Cytomegalovirus
- Varicella-zoster virus
- C. trachomatis serovar L target
- T. pallidum
- H. ducreyi
Candidiasis
- C. albicans
- C. glabrata
- C. tropicalis
- C. parapsilosis
- C. krusei
- C. lusitaniae
- C. dubliniensis
Bacterial Vaginosis
- Gardnerella vaginalis
- Atopobium vaginae
- Megasphaera type 1
- BV-associated bacteria 2
- Mobiluncus spp.
- Bacteroides fragilis
- Lactobacillus spp.
Which specimens can the clinic handle?
The clinic can handle the specimen types below, but not every specimen is valid for every panel.
Genital and liquid cytology
- Genital swab
- LBC: ThinPrep® or SurePath™
Urine and semen
- Urine collected to the selected test's instructions
- Semen when accepted for the selected module
Extragenital swabs
- Oropharyngeal swab (throat swab / ป้ายคอหอย)
- Anorectal swab
| 14-target panel | Urine or an appropriate site-specific swab, commonly genital or anorectal; exact laboratory acceptance is confirmed before collection. |
|---|---|
| Essential STI module | Genital swab, urine, semen, LBC, oropharyngeal swab, or anorectal swab. |
| Genital Ulcer module | Genital swab, urine, or LBC. |
| Candidiasis module | Genital swab, urine, or LBC. |
| Bacterial Vaginosis module | Genital swab or LBC. |
| Full 28-target option | Genital swab or LBC. |
What these PCR panels do not replace
- HIV: requires a separate blood-based HIV test selected according to the window period.
- Hepatitis B and C: require separate blood tests when indicated.
- Syphilis: standard serology remains important. A local-specimen T. pallidum PCR target does not replace blood testing when syphilis is suspected or screened for.
- Examination: ulcers, discharge, pelvic pain, testicular pain, proctitis, or recurrent symptoms may need physical examination and other tests.
- Antimicrobial susceptibility: PCR detects genetic targets but generally does not show which antibiotic will work; culture may be needed in selected situations.
How results are interpreted
- A detected target must be matched to symptoms, examination, specimen site, and whether that organism can be colonising rather than causing disease.
- A negative result covers only the organisms in the selected panel and the site sampled.
- Testing too soon, an unsuitable specimen, recent treatment, or low organism quantity can affect interpretation.
- Candida and BV-associated targets do not automatically mean an STI or that medicine is required.
- Partner testing, treatment, repeat testing, culture, or additional blood tests may be advised depending on the result.
Laboratory reporting is generally around three days, but exact timing can vary. The clinic will explain how results will be communicated and whether a follow-up consultation is needed.
Frequently asked questions
Which STI PCR panel should I choose?
The best panel depends on symptoms, exposure site, organisms of concern, and whether blood-based tests are also needed. The doctor can match the panel and specimen to your situation rather than automatically ordering the largest panel.
Can a urine STI PCR test detect throat or rectal infection?
Not reliably. Infection can be limited to the throat or rectum, so an oropharyngeal or anorectal swab may be needed when those sites were exposed. Specimen eligibility also depends on the selected laboratory panel.
Does the 28-target panel include everything in the 14-target panel?
No. The panels overlap but are not nested. For example, the 14-target panel includes Group B Streptococcus, while the 28-target option uses different grouped targets and does not include Group B Streptococcus.
Does a positive Candida or bacterial-vaginosis target mean I have an STI?
Not necessarily. Candida and BV-associated organisms can be present without a classical sexually transmitted infection, and detection alone does not always mean treatment is needed. Symptoms, examination, organism pattern, and clinical context matter.
Are HIV, hepatitis and syphilis blood tests included in these PCR panels?
No. HIV and hepatitis testing use separate blood tests. Although some molecular panels contain a Treponema pallidum target, local specimen PCR does not replace standard syphilis blood testing when serology is clinically indicated.
How long do STI PCR panel results take?
Laboratory reporting is generally around three days, but timing can vary with the panel, specimen, transport, and laboratory workflow. The clinic will explain the expected timing for the selected test.
References and related pages
Clinical guidance and clinic information used to support this guide.
Not sure which panel or specimen you need?
Contact Klaibaan Clinic with your symptoms, approximate exposure timing, and exposure sites. The doctor can help select an appropriate panel and explain the current testing options.