Do all patient need a maternal serum AFP level test?

MSAFP. Most women elect to have an msafp since it screens for neural tube defects, which can be very severe birth defects. The test is only done in the second trimester of pregnancy. Some women elect not to have the test.
Not all. Msafp is not mandatory, but a screening test for open fetal defects (neural, abdominal wall). If you are having a detailed anatomy ultrasound at 20 weeks, msafp is not necessary. It is also a marker of placental pathology, so it may be a good idea to have it screened anyway (not mandatory).