These criteria are used to help identify patients who may have HNPCC. Such patients should be considered for screening. The Amsterdam I criteria, see table 3 were considered too restrictive and were modified in 1999, see table 4. A patient is considered positive for the Amsterdam criteria if they match either set of criteria.
While the tables are difficult to remember exactly, they state what one may imagine from basic principles, several members of the family affected by the tumors, and young age at diagnosis.
| At least 3 relatives with colorectal cancer, one of whom shold be a first degree relative of the other two |
| At least two successive generations should be affected |
| At least one colorectal cancer shold be diagnosed before age 50 years |
| FAP should be excluded |
| Tumors should be verified by pathological examination |
| At least 3 relatives with an HNPCC-associated cancer
Colorectal Endometrial Small Bowel Ureter Renal Pelvis One of these relatives should be a first degree relative of the other two. |
| At least two succesive generations should be affected |
| At least one should be diagnosed before the age of 50 years |
| FAP should be excluded in the colo-rectal cancer case(s) if any |
| Tumors should be verified by pathological examination |