Hyperphosphatemic CKD dogs with stages 3-A, 3-B and 4 that also had an increase in uFEP may indicate that compensatory mechanisms were activated to avoid the development of hyperphosphatemia, and probably FGF-23 and PTH were acting to promote phosphaturia [23]; however in this current study, those biomarkers were not investigated [3,4]. This evidence concerns the gene PTH and hyperphosphatemia.