A 40-year-old man comes to the office with concern of HIV infection. The patient had unprotected anal intercourse with a new partner during a business trip a month ago. A few days after the encounter, the patient learned that the partner was HIV positive. The patient immediately visited an urgent care clinic and was tested for HIV using a combination p24 antigen/HIV-antibody immunoassay. Although the test was negative and he has no symptoms, the patient feels anxious about the possibility of infection. He has no prior medical problems and takes no medication. The patient drinks alcohol on social occasions but does not use tobacco or illicit drugs. Temperature is 37.1 C (98.8 F), blood pressure is 130/70 mm Hg, and pulse is 80/min. No oropharyngeal erythema, exudate, or ulcers are present. Lung auscultation is unremarkable and heart sounds are normal. The abdomen is soft and nontender with no organomegaly. Bowel sounds are normal. No anal ulcers are present and genital examination is normal.
Which of the following is the most appropriate next step in management of this patient's concern about HIV infection?

Question

A 40-year-old man comes to the office with concern of HIV infection.  The patient had unprotected anal intercourse with a new partner during a business trip a month ago.  A few days after the encounter, the patient learned that the partner was HIV positive.  The patient immediately visited an urgent care clinic and was tested for HIV using a combination p24 antigen/HIV-antibody immunoassay.  Although the test was negative and he has no symptoms, the patient feels anxious about the possibility of infection.  He has no prior medical problems and takes no medication.  The patient drinks alcohol on social occasions but does not use tobacco or illicit drugs.  Temperature is 37.1 C (98.8 F), blood pressure is 130/70 mm Hg, and pulse is 80/min.  No oropharyngeal erythema, exudate, or ulcers are present.  Lung auscultation is unremarkable and heart sounds are normal.  The abdomen is soft and nontender with no organomegaly.  Bowel sounds are normal.  No anal ulcers are present and genital examination is normal. 
Which of the following is the most appropriate next step in management of this patient's concern about HIV infection?

Quizplus · Accepted Answer

Explanation: This patient had an unprotected sexual encounter with an HIV-positive individual, putting him at high risk of infection. The recommended screening test for HIV combines detection of HIV antigen (p24) and HIV-1/HIV-2 antibodies. Although this test has excellent sensitivity and specificity, antigen and antibody titers are usually too low to detect for the first 1-4 weeks of infection (window period). Because 4 weeks have elapsed since this patient's high-risk encounter, HIV testing should now be repeated. (Choice A) This patient had a high-risk sexual encounter with an HIV-positive individual. Delaying testing prevents early initiation of antiretroviral therapy and puts his future partners at risk of potential infection (untreated viral load and unknown status). (Choice B) Although the risk of transmission is increased in those with high viral loads, this patient requires confirmatory testing to determine if he contracted HIV. (Choice C) Postexposure prophylaxis reduces the risk of HIV transmission but should be started <72 hours after exposure (ideally within 1-2 hours). After a month of potential infection, postexposure prophylaxis would not be helpful. (Choice D) This patient was initially tested a few days after potential exposure; screening tests are almost always negative shortly after infection as antigen/antibody titers are still too low to be detected. Educational objective: Patients at high risk of HIV exposure should receive a screening test that combines detection of HIV antigen (p24) and HIV-1/HIV-2 antibody. False-negative results may occur during the first 4 weeks of infection due to low titers of antigen and antibody (window period).

A 40-Year-Old Man Comes to the Office with Concern of HIV