The machines for this test are not approved in the US. Secondly even if that was waived, there it the issue of getting the machines here, setting them up and training people in the lab. And the reality is a huge number of countries also want these tests.
I've read however that FDA just approved a new test on Roche lab equipment which many labs already have.
https://www.cnbc.com/2020/03/13/scott-gottlieb-us-to-conduct...