How did the doctor's appointment go? What did the doctor say about plasma renin blood test (I assume your child has classical salt wasting CAH). Plasma renin blood work is always taken for the Addison's or CAH hypoplasia patient and the salt wasting CAH child (I am not sure about the non-salt waster). To make sure the florninef is working. And since they have to poke the child (or adult) for that test ... why not check the other blood levels that way too. And yes, the urine can be used a double check. Check both would be my preference. And at least every three month for a growing child. More often if blood work does not look right (too high or too low).