In Germany people that were tested positively are not tested again, meanwhile people that were tested negatively are tested again.
I wonder why they would do that.
t. someone working at a hospital
(and I personally see that some patients are tested 5 times within a few days, only one comes back as positive and the patient is then marked as "confirmed China virus". We even had patients on intensive care, who tested positively at the start, and then later tested negatively despite their symptoms got way worse).