CDC has released updated guidance online for U.S. laboratory testing for Zika virus infection. The guidance is available at https://www.cdc.gov/zika/laboratories/lab-guidance.html. Frequently asked questions are addressed at https://www.cdc.gov/zika/laboratories/lab-guidance-faq.html. This guidance updates recommendations for testing of specimens by U.S. laboratories for possible Zika virus infection. Major updates to the guidance with clinical implications for health care providers include the following.