In other words, an increase in creatinine in a young bodybuilder does not always indicate kidney failure [64,65], a rise in NGAL is not always related to acute kidney failure [66,67], interpreting Cystatin C requires understanding of pharmacological treatments [68,69], and copeptin appears to be a reliable marker of kidney function in autosomal dominant polycystic kidney disease but has not been tested in other disorders [70,71,72,73]. This evidence concerns the gene AVP and kidney failure.