Although at the start of the week President Biden was upbeat about not needing further travel restrictions yet, three days later the White House have announced that they will be changing the testing rules from “early next week” but no exact date has been given yet.
The rules mean that all those entering the US that are required to have a negative test will need to have that test within one day (not 24 hours) of arrival. This means you only have two options: a 3 hour rapid PCR test which you can get from companies such as Collinson and Express Test. Or a lateral flow/rapid antigen. These are cheaper but the test must either be in a testing centre or supervised by video. Project Screen and Qured are amongst those offering the video appointments with Express due to follow in mid December.
The testing does not apply to children under two.
The FCDO have yet to update their advice but the White House have formally issued the change
You can find the full details of the CDC requirements here.