Hi healing light, I had a colonoscopy in february because I complained of parasites.it was very painful, it felt like a bus driving thru my abdomen and the Gastro doc declared there was nothing there. Here are some comments:
1) They give you an enema the day before to ensure your colon is completely empty of food etc. That could probably wash out any pin worm in the large bowel.
2) it did not look to me as though the camera had sufficient resolution to identify pinworm.
3) Quite a lot of parasites are in the small intestine. The camera is not designed to go much further than the large intestine.
4) A colonoscopy is used to look for cancers/growths/disease of the bowel, not parasites.
Of course I did have paraites -strongyloides, but the camera could not reach up into the small intestine. it was a waste of time, money and pain.
You might ask your doc why she suggests a colonoscopy? Is it to look for parasites or to check there in nothing else wrong in the bowel.