The U.S. Food and Drug Administration advises all blood donations be tested for Zika virus.
The Arizona State Health Department says it is certified to test for Zika. However it tests people, not donations.
One of the biggest blood bank in the country, American Red Cross, is not currently following the FDA recommendation.
Red Cross is testing blood donations in only some states.
In a statement the organization states: "The Red Cross is conducting blood donor tests for Zika virus under an investigational study in five southeastern states in the U.S. that are believed to be at greatest risk of local mosquito transmission of Zika virus in which our collections occur."
The five southeastern states are Alabama, Florida, Georgia, South Carolina and Mississippi.
The organization plans to later expand the study to Arizona, Texas, Oklahoma and California over the next two weeks.
Arizona is a high risk state for Zika, according to the Centers for Disease Control and Prevention.
By not monitoring all blood donations in Arizona, there is a possibility for Zika to spread.