It has been a while since I have been on here but I would like to correct some of the advice given here.
If your dog has tested as a CARRIER, and has come from untested dogs, or ANY breeding that could produce an AFFECTED, YES YES YES you need t strip test your dog.
There have been 5 (this might be 4) dogs that have tested multiple times as a Carrier, but are AFFECTED. They were from untesteds or from breedings that could have produced an Affected.
The only way to be able to catch Fanconi as soon as the dog starts to spill is to test. The earilest I have heard of spilling is 2.5 years of age.
Also, pups can be tested as early as 2 weeks of age, I have done this and their was more than enough DNA for the tests to be ran.