How is NASAP affected when a worker changes contractor companies?

For example, Person A was hired by Contractor X and is tested by one of the TPAs. Later the same worker is hired by Contractor Y that uses a different TPA. Does the person need to be tested again? How is the TPA aware that the worker is already in the NASAP pool? The worker will stay “Active” on the NASAP database if he/she does not miss a random test or tests non-negative regardless of who the worker’s employer is. Contractor Y must do a NASAP look-up to see if Person A is in the database and discern their status. Person A does not have to be re-tested unless the database shows the individual is “Inactive”. It is the responsibility of the employer to call the TPA to determine why the person in “Inactive”.