As I mentioned in a recent forum post, a reader sent us a question about looking for blood in your child’s stool when reintroducing food.   She wanted to know if we used guaiac cards, which I had never heard of.  A quick search shows that guaiac cards are used for detecting occult fecal blood.  These cards can be used to detect blood in a stool sample that is not visible to the naked eye.
We’ve never used these cards, and they have never been mentioned to us by any health care …