A mineral found mainly in the bones, where it is stored. Calcium is essential for healthy bones and many other functions of the body. Due to a change in the balance between the two important minerals calcium and phosphate renal osteodystrophy is common in patients with chronic renal failure. Renal osteodystrophy results in a loss of calcium from the bones and thus to thin and weak bones, which break easily or begin to hurt.

Chronic renal failure is synonymous with chronic kidney disease (stage 5) or chronic kidney failure. Unlike acute renal failure chronic renal failure is a slowly worsening loss of kidney function. Chronic renal failure can range from mild dysfunction to severe organ failure. The disease may lead to end-stage-renal-disease (ESRD) and finally to renal replacement therapies.

A chemical waste molecule that is generated from muscle metabolism. Creatinine is produced from creatine, a molecule of major importance for energy production in muscles. Approximately 2% of the body's creatine is converted to creatinine every day. Creatinine is transported through the bloodstream to the kidneys. The kidneys filter out most of the creatinine and dispose of it in the urine. Creatinine serves a vital diagnostic function, because its levels turned out to be a fairly reliable indicator of kidney function. As the kidneys become impaired the creatinine will increase, sometimes before any symptoms are reported. Normal levels of creatinine in the blood are approximately 0.6 to 1.2 milligrams (mg) per deciliter (dl) in adult males and 0.5 to 1.1 milligrams per deciliter in adult females. Creatinine levels of 10.0 or more in adults may indicate the need for dialysis.