Inclusion Criteria:  Major patient, male or female Taken care of at the Clermont-Ferrand University Hospital or the Jean Perrin Centre In a context of hypophosphatemia (< 0.80 mmol/L), without immediate anteriority and not occurring during hospitalisation In capacity to express informed consent to participate in research Affiliated to a social security system  Exclusion Criteria:  Previously diagnosed hypophosphatemia Hypophosphatemia during hospitalisation Haemodialysis patient Refusal to participate