STI Blood Panel for Female Patients with PID or Cervicitis
For females presenting with PID or cervicitis, collect blood for HIV antibody/antigen testing, syphilis serology (treponemal-specific test followed by RPR), hepatitis B surface antigen, and hepatitis C antibody, while simultaneously testing cervical/vaginal specimens for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. 1, 2
Core Blood-Based STI Testing
The essential blood panel includes:
HIV testing: Use enzyme-linked immunoassay (EIA) for both HIV-1/2 antibodies and antigen as the initial test, with repeatedly reactive results confirmed by Western immunoblot 2. HIV screening is mandatory for sexually active patients aged 13-64 seeking evaluation for STIs 1.
Syphilis serology: Most laboratories use a reverse screening algorithm with treponemal-specific test first (EIA/chemiluminescence immunoassay) followed by nontreponemal testing (RPR) to confirm 1, 2. This is a required reportable test 1.
Hepatitis B surface antigen (HBsAg): Screen for hepatitis B infection 2. Consider adding hepatitis B core antibody (HBcAb) and hepatitis B surface antibody (anti-HBs) for complete immunity assessment 2.
Hepatitis C antibody: Include in the initial blood panel 2.
Critical Non-Blood STI Testing (Cervical/Vaginal Specimens)
Testing simultaneously for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas is optimal for detection of the most common treatable STIs in female patients 1:
Chlamydia and gonorrhea: Use nucleic acid amplification tests (NAATs) on cervical or urine samples, as these are the most sensitive and specific tests available 1, 3. Laboratory documentation of cervical infection with N. gonorrhoeae or C. trachomatis supports the diagnosis of PID 3.
Trichomonas: Include in simultaneous testing panel 1. Standard wet mount microscopy misses 30-50% of cases; more sensitive methods include culture, nucleic acid probe, or PCR 4.
Important Clinical Context
Why This Testing Matters for Morbidity and Mortality
PID results from untreated bacterial infections, primarily chlamydia and gonorrhea, and can lead to infertility, ectopic pregnancy, and chronic pelvic pain 5, 6, 7. The inflammatory epithelium in cervicitis enhances HIV transmission risk, making HIV screening particularly critical 1, 2. Early recognition and appropriate antibiotic therapy are essential to prevent these serious sequelae 8.
Emerging Pathogen Consideration
Mycoplasma genitalium is increasingly recognized as a cause of cervicitis and PID in females 1. However, standardized diagnostic tests are not yet commercially available 1.
Partner Management is Non-Negotiable
Sexual contacts must be evaluated and given presumptive treatment to prevent reinfection, as most treatment "failures" represent reinfection from untreated partners 1, 2, 3. This is essential for reducing morbidity in the index patient 1.
Special Populations Requiring Additional Testing
Pregnant women: Repeat HIV and syphilis testing in the third trimester even if previously tested 1, 2. Add Group B streptococcus screening at 35-37 weeks using both vaginal and rectal swabs 1.
High-risk individuals: Consider extragenital site testing (rectal, oropharyngeal) for gonorrhea and chlamydia if the patient has risk factors such as multiple partners 1.
Common Pitfalls to Avoid
Don't wait for test results to treat: Empiric treatment should be initiated as soon as the presumptive diagnosis of PID is made 3. Treatment regimens must provide broad-spectrum coverage effective against N. gonorrhoeae and C. trachomatis even with negative endocervical screening 3.
Don't rely on clinical diagnosis alone: Clinical diagnosis of genital infections is neither sensitive nor specific, making diagnostic testing essential 1.
Don't forget that 25-40% of genital infections may not be specifically identified despite comprehensive testing 1.