The Next Step - AFP Only Screen
We have introduced a new patient pamphlet to address the recommendation that patients who have had a normal Early Screen® test have an AFP ONLY test or ultrasound examination in the second trimester. Publications have documented that patients that have first trimester screening should not have second trimester chromosome screening because:
1) The screen positive rate will rise from less than 2.4% to 17% which means about 1 in 6 patients would have a conflicting and confusing test result in the second trimester. For most of these patients, increased anxiety will result in unnecessary diagnostic amniocentesis.
2) The yield would rise from 1 in 17 patients having a CVS or amniocentesis to detect one affected fetus to approximately 1 in 250 if chromosome screening is repeated in the second trimester.
3) A follow up triple or quad screen is not standard of care because these tests are being applied to a previously screened population with over 90% decreased incidence of affected fetuses with the new risk estimate and the different biochemistry for these patients.
4) A follow up chromosome screen risk assessment will not be accurate (Benn, Journal of Genetic Counseling, December, 2005). Each screen negative Early Screen patient will have a new risk estimate after screening. Second trimester labs do not have appropriate databases to deal with this new risk and the different biochemistry for those screen negative patients.
The 'After Early Screen® AFP The Next Step' pamphlet can be provided to your patients in the first trimester with their Early Screen pamphlet so they can provide consent to have Early Screen followed by AFP only or ultrasound in the second trimester. Please call our genetic counselors if you have questions, or if we can assist with providing information to you and your associates about the recommended follow up for Early Screen testing.