<prompt> Anencephaly is best diagnosed using:Maternal serum alpha feto proteinAmniotic fluid alpha feto proteinUSGX-ray  <response>: 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 AnencephalyNTD in brief:Best screening test for NTD: Maternal serum alpha protein between 14 and 22 weeks, best at 16 weeks.Best marker for NTDOpen spina bifida Anencephaly is Acetylcholinesterase.Best investigation for Anencephalyultrasound.Best time for diagnosis of Anencephaly is 14 weeks by USGEarliest diagnosis of Anencephaly by 10 weeks.Best investigation for hydrocephalus is Ultrasound. 