US health officials have granted the use of an experimental blood test to screen for Zika virus, an emergency step that will help protect local blood supplies from the mosquito-borne infection.
The action means US territories with active Zika infections, primarily Puerto Rico, will be able to resume collecting and screening their own blood.
Previously, the island of 3.5 million barred local donations and began importing blood from the US, following recommendations from the US Food and Drug Administration (FDA).
The FDA said that use of the test, from the drug company Roche, could be expanded if the virus spreads to other areas of the US.
Currently, no US states have reported local, mosquito-transmitted Zika cases.
Puerto Rico has 350 confirmed cases of the virus, including 40 pregnant women.
Some experts believe many of the problems experienced in Puerto Rico now may be repeated later this year in Florida, Texas and other southern US states where officials think mosquito-borne outbreaks of Zika may occur.
Dr Peter Marks, director of FDA's centre for biologics, said: "In the future, should Zika virus transmission occur in other areas, blood collection establishments will be able to continue to collect blood and use the investigational screening test, minimising disruption to the blood supply."
The Virgin Islands and American Samoa have also reported Zika cases, but both territories already import blood donations as a standard practice.
The test authorised by the FDA is made by Roche Molecular Systems, a division of the German healthcare conglomerate.
Zika is spreading rapidly through Latin America. While most people experience either mild or no symptoms, Zika is suspected of causing a devastating birth defect - babies born with abnormally small heads - and pregnant Americans have been urged to avoid travel to affected areas.
Puerto Rico has 350 confirmed cases of the virus, including 40 pregnant women. Two of those women have given birth to healthy babies. Health authorities have said they are not tracking suspected cases.
Last week, the Centres for Disease Control and Prevention (CDC) said birth control supplies are badly needed in Puerto Rico to help prevent unintended pregnancies during an outbreak of Zika there.
Earlier this month, the CDC and the FDA authorised emergency use of a separate laboratory test to diagnose Zika infection in patients. The test was distributed to a limited number of US and international laboratories.
FDA Allows Use of Investigational Test to Screen Blood Donations for Zika Virus https://t.co/P58Q31xASC pic.twitter.com/zzwnjZ1Ipk— U.S. FDA (@US_FDA) March 30, 2016