Again from the Women’s Surgery Group:
It has been estimated that the diagnosis of endometriosis is missed in more than 7% of patients, and the extent of disease is underestimated in as many as 50% of patients.
From the context, it would seem that the 7% and 50% refer to patients who have undergone diagnostic laparoscopy. Reading the whole page, I don’t think it accounts for patients whose diagnoses are missed because no laparoscopy is performed.
