If you get a test through OFA (the only way to get one), the results will come back very clearly marked. Either "Probably Carrier" "Probably Clear" "Probably Affected" or "Indeterminate between Clear and Carrier." Its very difficult to misinterpret the results.
A basenji that is a carrier can be bred (technically, any basenji can be bred, regardless of results), but the question is, why? You would not want to breed an affected dog because it not only perpetuates carriers of Fanconi, but it also puts stress on that individual dog, which makes it more likely Fanconi symptoms will show themselves sooner rather than later.
A carrier can be bred, if done carefully, and only if that particular individual has a lot to offer the breed. That's a matter of opinion amongst breeders; some will never breed a carrier just to avoid the risk of perpetuating Fanconi, and some will breed a carrier to a clear if the dog is a particularly remarkable dog conformation, performance, temperament, health wise.
So, regardless what your dog's test results are, Fanconi results are not the only factor you want to look at for breeding.
This is my layman's understanding; I'm sure the breeders can chime in and give you better insight into their own opinions and practices.