On 9/8/16 employee demonstrated a STS, left ear. Employee stated that they had a double ear infection. As per MSHA and IHT employee retested on 10/5/16. IHT sent a letter stating they couldn't verify the results due to an obstruction of wax in ear. We had employee tested again on 10/13/16 where they again demonstrated the STS. I received the results of that test today 10/25/16.