The excretion of sodium varies with dietary intake. There is a diurnal variation of sodium excretion with excretion being greater during daytime than during the night. Decreased levels are seen in congestive heart failure, excessive sweating, diarrhea, pyloric obstruction, malabsorption and primary aldosteronism. Increased levels may be due to increased salt intake, failure of the adrenal glands, diabetic acidosis, salt losing renal disease, diuretic therapy and water deprivation dehydration. The creatinine value provides evidence of proper 24 hour urine collection.