Background: Anemia is commonly observed in the course of chronic kidney disease (CKD) and it is 
associated with diminishing the quality of a patient's life. It also increases morbidity and mortality 
and CKD progression rate, so it is critical to continue investigations that help explain risk factors 
involved in the development of anemia in CKD. FGF23 is a promising biomarker of adverse 
outcomes in patients with CKD. Several studies have suggested a possible association between 
FGF23 and anemia in these patients. The aim of the current study was to detect level of FGF23 in 
CKD patients and clarify the relation between of FGF23 level and anemia in CKD patients. Subjects 
and Methods: Subjects: This case - control study was conducted on 90 subjects at the nephrology 
department of Minia University Hospital through the period from March 2019 to November 2019 
selected and divided into three groups containing both control and patients groups. Group І included
30 patients with chronic kidney disease, not on hemodialysis, Group ІI included 30 patients with 
chronic kidney disease on Hemodialysis and both are with anemia. Group ІII included 30 individuals 
who are the healthy group. Exclusion criteria: Pregnancy, liver cirrhosis, Polycystic kidney disease, 
Renal cancer, Recent chemotherapy or immunosuppressive therapy, New York Heart Association 
class 3 or 4 heart failure, Multiple myeloma, Overt gastrointestinal diseases such as untreated gastric 
cancer and ulcers, Abnormalities of the white blood cell count and differential or platelet count.
Laboratory methods: A)Blood sampling protocol: 6 ml of blood was withdrawn by sterile 
venipuncture and before dialysis session in the second group, left to be clotted then centrifuged and 
the separated serum was divided into liquates. One was designated for the immediate assessment of 
routine chemistry, The rest of serum was stored at -5 c for subsequent assay of specific labs. B) 
Routine laboratory Investigations: Using the commercially available kits, all patients underwent 
full laboratory investigation including Complete blood count (CBC) and Renal function tests (serum 
urea and creatinine). C) Specific investigation: eGFR, HS-CRP, Iron profile (serum Iron, Ferritin, 
TIBC), calcium (Ca), phosphate (P), intact (i)-PTH level and i-FGF23 level. D) Imaging studies:
Abdominal ultrasound was performed by General Electric ultrasound and transducer with a frequency 
of 3.5 megahertz (MHz), USA. Statistical analysis: Statistical analysis was conducted using the 
Statistical Package for Social Sciences (SPSS software version 25). Results: Elevated FGF23 
inversely correlated with iron deficiency anemia in patients with CKD dialysis patients of statistical 
significance (P=0.012). Conclusion: FGF23 levels in CKD are higher than levels observed in healthy 
patients, elevated FGF23 inversely correlated with iron deficiency anemia in patients with CKD 
patients, and with high sensitivity and specificity of FGF23 as a promising marker for prediction of 
disease progression.