Renal tubular acidosis is a condition or disease in which the kidney does not take acid out of blood and put it into urine like it should. Protein is broken down to yield energy and amino acids, and the amino acids are used to make new proteins. Acid is generated as a waste product in this process, and the part of the kidney called the tubule takes the hydrogen ions, the acid molecules, out of the blood and puts them into the tubular fluid, which ultimately becomes urine. The kidney defect is limited to this, although along with it comes some decrease in the ability to concentrate the urine, meaning the ability to put a large amount of waste products into a small amount of urine. This ability is crucial in times of decreased fluid intake, or during increased fluid losses, like during episodes of diarrhea and vomiting. So the child with RTA becomes more easily dehydrated under these circumstances. Sometimes parents or doctors will be fooled about the dehydration, because lack of urinary concentrating ability means that the child keeps urinating fairly frequently. Frequency and amount of urination cannot be used as a marker of hydration.