December 27, 2023

The U.S. Food and Drug Administration (FDA) is reminding health care providers and clinical laboratory staff about the potential for false reactive (false positive) results in herpes simplex virus type 2 (HSV-2) serological tests for genital herpes. 

Recommendations 

The FDA recommends that health care providers and clinical laboratory staff do the following:   

• Review the CDC guidelines before ordering HSV-2 serological testing to reduce the risk of false reactive results. 
• Be aware that false reactive results can occur.  
• Counsel patients about the limitations of available testing before obtaining HSV-2 serologic tests. 
• Perform confirmatory testing for reactive results as provided in the test’s labeling and in accordance with professional guidelines, such as Biokit or Western blot tests. 

Background 

According to the Centers for Disease Control and Prevention, clinical diagnosis of genital herpes can be challenging. When using the current HSV tests, the chance of a false result increases if a person:

• gets a blood test too soon after infection
• has a low risk of infection
• receives test results that are near the cutoff (low positive)

FDA Actions 

We are providing this information to help educate health care providers and clinical laboratory staff and reduce the risk of false results. The FDA will continue to keep health care providers and clinical laboratory staff informed if new or additional information becomes available. 

Reporting Problems to the FDA 

The FDA encourages users to report false reactive results with HSV-2 serological tests.  

• You can submit voluntary reports through MedWatch, the FDA Safety Information and Adverse Event Reporting program. 
• Device manufacturers and user facilities must comply with the applicable Medical Device Reporting (MDR) regulations. 
• Health care personnel and clinical laboratory staff employed by facilities that are subject to the FDA's user facility reporting requirements should follow the reporting procedures established by their facilities. 

By promptly reporting adverse events, you can help the FDA identify and better understand the risks associated with medical devices. The FDA regularly monitors the post-authorization use of tests, including reports of problems with test performance or results. 

Contact Information 

If you have questions about this letter, contact the Division of Industry and Consumer Education (DICE).