Amniocentesis test

mehulp1184

I have an AFP test and it came abnormal at 102.3 ng.mL and MoM of 2.68 went for an ultrasound but did not detect anything the primary doctor told us to do Aminocentesis but at that time I was week 20 and 2d doctor told us that I shouldn’t decline the Amniocentesis test because in the ultrasound does not detect and it is not accurate. I had a trisomy test everything came back as normal does anyone have a similar issue please let me know I am worried.