Very low bicarbonate values are indicative of hypoperfusion, stool losses or both. Poor intake may result in a relative hypoglycemia. Stress related glucocorticoid release may result in a relative hyperglycemia. New onset diabetes may present as vomiting and volume depletion. Hypernatremic dehydration may present with hyperglycemia, which may confuse the diagnosis.
Urine studies are useful to grade severity of volume depletion.
Urine tests also should be considered in the workup of gastroenteritis, urinary infection, diabetic ketoacidosis, or renal tubular acidosis. Newborn infants may have a falsely low specific gravity, as their kidneys may not yet be able to concentrate urine. Ketonuria is typical of anorexia. Large ketones may suggest diabetes. Abdominal films are not routinely needed.