I am curious to know if this is actually possible. I did a home pregnancy test as my period is quite late (I do have an irregular cycle sometimes) and the test showed negative. The next day out of curiosity I peed on the same test and it came up positive. Is this posible?
Thank you in advance.

The ONLY way to use home tests is as described in the accompanying instructions.
They are SINGLE use by design.

It is, you're washing the chemicals from the control over to the test area. So it will be positive, not because you're pregnant but because you're using the test in a manner that won't give anything close to an accurate result.

Buy anther test and follow directions.

Often they will show positive just sitting there for a long period, after one use. They are only for one use. This was not a valid test.