Children are tested for Peutz-Jeghers syndrome by performing an upper gastroenterology (GI) endoscopy and a colonoscopy. These procedures allow the doctor to look inside the esophagus, stomach, duodenum, and large intestine using separate long, flexible tubes with cameras on the end.
The small intestine is examined using a wireless capsule endoscope.
Another way to test for PJS is through genetic testing. Identifying the PJS-mutation in the STK11 gene is very accurate with a detection rate of more than 90 percent.
Other testing may include radiology imaging, such as MRI.