False-Positive Human Immunodeficiency Virus-1 Test Results With Rapid Seroreversion After Third-Trimester Tdap...

Area of Science:

• Immunology
• Infectious Diseases
• Obstetrics and Gynecology

Background:

• False-positive human immunodeficiency virus (HIV) test results can occur due to various factors, including pregnancy, autoimmune conditions, and infections.
• Previous reports have documented false-positive HIV tests in specific clinical scenarios, necessitating careful interpretation.

Purpose of the Study:

• To report an atypical case of false-positive HIV test results in a pregnant patient following routine vaccination.
• To highlight the potential for immune system triggers, such as vaccination, to cause transient reactivity in HIV diagnostic assays.

Main Methods:

• A case study of a 34-year-old pregnant woman with a negative initial HIV test.
• Administration of a tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine booster late in gestation.
• Serial HIV testing, including screening and confirmatory assays, performed after vaccination.

Main Results:

• The patient initially presented with positive results on both HIV-1/2 antigen-antibody screening and HIV-1 antibody differentiation immunoassay.
• Subsequent HIV testing performed shortly after the initial positive results demonstrated rapid seroreversion to negative.
• Laboratory error and specimen mishandling were ruled out through repeat testing and erythrocyte typing.

Conclusions:

• Receipt of a Tdap vaccine booster 7 days prior was associated with false-positive HIV screening and confirmation test results.
• The rapid shift from positive to negative HIV test results suggests an acute immunologic trigger, likely related to the vaccine.
• Clinicians should consider recent vaccination or other immune triggers as potential causes of false-positive HIV tests and retest patients promptly if suspected.