Explore a crucial aspect of HIV management with this scenario-based USMLE Step 2 CK question. Learn about recommended screening tests for newly diagnosed HIV-positive patients.
A 32-year-old biologically female patient presents to the primary care office for an initial visit after learning she is HIV-positive from a screening test. The patient does not have symptoms. Her past medical history is otherwise unremarkable, and she does not take medication. The patient is sexually active with one male partner. Temperature is 37.0°C (98.6°F), pulse is 90/min, blood pressure is 128/82 mmHg, and respiratory rate is 16/min. Physical examination is within normal limits. Which of the following screening tests should be performed at this time?
A. Nucleic acid amplification testing for trichomoniasis
B. Hepatitis B e-antigen
C. Vaginal culture for bacterial vaginosis
D. Treponema pallidum passive particle agglutination
E. Anti-Hepatitis A IgM antibodies
Scroll down for the correct answer!
The correct answer to today’s USMLE® Step 2 CK Question is…
A. Nucleic acid amplification testing for trichomoniasis
Before we get to the Main Explanation, let’s see why the answer wasn’t B, C, D, or E. Skip to the bottom if you want to see the correct answer right away!
Incorrect answer explanations
Today’s incorrect answers are…
B. Hepatitis B e-antigen
Incorrect: The recommended screening tests included in the hepatitis B screening panel are: hepatitis B surface antigen, antibody to hepatitis B surface antigen, and total antibody to hepatitis B core antigen.
C. Vaginal culture for bacterial vaginosis
Incorrect: Routine screening for bacterial vaginosis (BV) is not recommended. When indicated based on symptoms, the preferred tests for BV are saline microscopy or nucleic amplification testing.
D. Treponema pallidum passive particle agglutination
Incorrect: This patient should be screened for syphilis (caused by Treponema pallidum) with a non-treponemal test first, either a Venereal Disease Research Laboratory (VDRL) or Rapid Plasma Reagin (RPR). If that testing is positive, it should be followed by a treponemal test, such as the T. pallidum passive particle agglutination (TP-PA) test.
E. Anti-Hepatitis A IgM antibodies
Incorrect: Patients with HIV should be screened for hepatitis B and C and vaccinated against hepatitis A and B. This patient does not have an indication to check hepatitis A antibodies.
Main Explanation

This patient who has been newly diagnosed with HIV infection should have screening for trichomoniasis using nucleic acid amplification testing, as well as a baseline screening for other infectious diseases. Continued annual screening for trichomoniasis should be considered for patients with HIV infection.
The testing for a patient presenting for sexually transmitted infection (STI) screening varies depending on the patient’s risk factors for STIs. HIV infection is an indication to increase the frequency of testing from what is recommended for the general population, as well as to expand the types of tests done beyond what is needed for low-risk patients. Screening for STIs is indicated at the first evaluation following a new diagnosis of HIV and includes testing for gonorrhea, chlamydia, trichomoniasis, syphilis, and hepatitis B and C. Screening for gonorrhea and chlamydia, trichomoniasis, and syphilis are then repeated at least annually. Human papillomavirus (HPV) and cervical cancer screening is based on routine guidelines for individuals with HIV. Herpes serology testing may also be considered in this population.
Additional factors to consider include patient age (annual for under age 25), pregnancy status, sexual practices including having new or multiple partners and having a sexual partner who has other concurrent partners, as well as living in an area with a high prevalence of disease. Men who have sex with men should also be screened frequently (at least annually) and in some cases as often as every three to six months.
Major takeaway
Patient risk factors determine the frequency and type of sexually transmitted infection screening indicated. Patients with HIV infection should be initially screened for gonorrhea, chlamydia, trichomoniasis, syphilis, and hepatitis B and C.
References
Centers for Disease Control and Prevention: STDs during Pregnancy – CDC Detailed Fact Sheet. Last Reviewed: April 11, 2023. Accessed December 19, 2023. https://www.cdc.gov/std/pregnancy/stdfact-pregnancy-detailed.htm#:~:text=NOTE%3A%20Pregnant%20women%20found%20to,be%20retested%20within%20three%20months
Centers for Disease Control and Prevention: Screening Recommendations and Considerations Referenced in Treatment Guidelines and Original Sources. Last reviewed: June 6, 2022. Accessed December 19, 2023.
Lee, Karen C. MD et al. Sexually Transmitted Infections: Recommendations from the U.S. Preventive Services Task Force. American Family Physician. 2016;94(11):907-915.
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