Probably the common cold or 'flu.
The man credited with the invention of the 'Covid' test protested vociferously as his original process was distorted in order to magnify the result. As expected, the controlled media wouldn't allow you to hear a word of this as it goes against the agenda.
This resulted in the test having the ability to detect whether or not someone had had the common cold within the previous three months, so this is what they found in you/your mum.