Anencephaly is best diagnosed using:

“In the early days of AFP screening, an elevated maternal serum AFP level prompted amniocentesis to determine the amniotic fluid AFP level. If the AFP level was elevated, then an assay for acetylcholinesterase was done. These tests were considered diagnostic for fetal NTD. Today however nearly 100% of NTDs are identified by ultrasonography used alone.” Diagnosis of Anencephaly/NTD in brief: Best screening test for NTD: Maternal serum alpha protein (between 14 and 22 weeks, best at 16 weeks). Best marker for NTD/Open spina bifida/ Anencephaly is Acetylcholinesterase. Best investigation for Anencephaly—ultrasound. Best time for diagnosis of Anencephaly is ≥ 14 weeks by USG Earliest diagnosis of Anencephaly by 10 weeks. Best investigation for hydrocephalus is Ultrasound.