Birmingham City Council mistakenly handed out around 25 coronavirus testing swab kits to students.
The kits were accidentally delivered in the Selly Oak area as part of the council's drop off and collect service.
The council has launched an investigation into the blunder which occurred as workers went door-to-door in Tiverton Road on Tuesday.
The council confirmed "a small number" of tests were mistakenly handed out during their drop and collect.
Second year medical student Tasha Ashbridge told student news site The Tab: "The tests were sealed but we obviously didn't expect that to mean they were used."
Her housemate, Sophie Dunne, also a second year medic, told the site: "This was the first at home test I had done.
"After opening the test I could see that they had already been completed due to snapped off swabs in the test tube and sealed bag."
Fortunately, the students made the discovery before using the kits and alerted the council workers who were handing out tests up the road.
She added: "When I went back to them there were loads of people at their doors saying the same thing. It's such a scary thing to happen."
"I would have at least thought the workers would have been advised what packaging was supposed to look like in event of tampering or contamination.
"The tests were quickly recollected but students weren't given any info on what to do as obviously all the tests had been mixed up."
According to the Daily Mail, the council initially said the incident involved seven houses and 25 kits.
The council are now said to have carried out an investigation overnight, which found there was "no evidence of cross-contamination".
A spokesperson further added that there would be a "root and branch review" into the incident.
A council spokesperson told Mirror Online: "We are aware that a small number of tests were mistakenly given out during Drop and Collect activity in Selly Oak yesterday (13th Oct).
"As soon as it became apparent that the wrong tests had been given out steps were taken immediately to rectify the mistake.
"Drop and Collect is a vital part of helping to tackle the spread of Covid in our City, with 100,000 tests being undertaken to date.
"The circumstances around this incident are being fully reviewed and any required changes to process will be implemented."
