###Human: Does trisomy 21 of 1:250 report show high risk? ###Assistant: Hello. 1 in 250 is a high risk for trisomy which means your risk of having a baby with trisomy 21 is 1 out of 250. But this test is only a screening test which means that they just calculate the risk of having a baby with down syndrome. If someone is found at higher risk like yours, then she is offered a diagnostic test (amniocentesis or chorionic villus sampling). In those tests, a sample of fluid is taken from your baby and examined in labs to confirm the diagnosis accurately.