Don't need to worry too much for the time being. All screening methods have a certain "false positive" rate: i.e. the proportion of infants without hearing loss who are labeled incorrectly by the screening process as having significant hearing loss. Usually it's about 3-5 %, depends on the method used, skill of the nurses etc.
That's also the reason why they test 2 times before referring for a detail hearing check.
For the time being, observe and wait, don't need to worry too early!
;-) How is your baby's hearing? Ask an audiologist! ;-)