Alpha-fetoprotein

A protein made by the fetal liver, produced again by some liver and germ-cell tumours.

It is used to monitor people with chronic liver disease, and in that setting a rising value is the part that matters.

Any active liver disease raises it, including hepatitis and cirrhosis without cancer, and it is high in pregnancy for entirely normal reasons. A single value out of context is not interpretable.

Worth discussing a rising trend together with liver enzymes.