My boss had me do this test recently, and I came up with INTP multiple times and it seems to describe me well, but not when I am at home.
More than one person has commented that I seem a completely different person around my younger siblings, and I have to agree with them. To others I come off as cold, sarcastic, and overly analytic, to the point several people have stated openly their belief I would be a cold and inept caregiver. On the other hand, when co-workers (rarely) see me with my siblings they express absolute surprise at my interactions with them. My closest friend at work acted like I lead a secret double life when he met my brother and sisters.
As a test I had my three siblings fill out the test for me and I got a ISFJ and almost an INFJ with overwhelming tendency toward F and J. I had them read over INTP and they laughed at the idea it could ever be used to describe me. I admit they know me best, but I also think perhaps they are biased due to 1 Age, and 2 how close we are. Perhaps they gave me the traits they think are best than more accurate.
I was curious if maybe I just seem like an INTP at work and with other family, or I learned to be more receptive to them because they relied on me so heavily for emotional needs at an early age. I admit in most things I am fairly rational, but not when it comes to them. They believe me to be a "goofball", patient, and doting, while others, including myself, view me as cold, harsh, and wrapped up in my own thoughts. Is it possible to be both?