I'm wondering can the embryo be tested for krabbe disease?

Yes, PGD is possible: Krabbe disease results when both parents carry a gene for this disease and a child inherits two abnormal genes, one from each parent. We know which gene is responsible for this disease, so Preimplantation Genetic Diagnosis (PGD) where we test embryos for the disease before replacing disease-free embryos or carriers back into the mother's uterus, should be possible. This is a form of IVF treatment.