Cholestasis test- need name of test

Please help! I’m almost 26 weeks and I think I might have cholestasis, due to extreme itching that comes and goes but is worse at night, and has moved to my feet and hands. I requested a blood test at my OB. They really blew me off and I had to get pushy to get them to give it to me. The results came back within a few hours and everything I read said the test takes up to a week because there are only 2 labs in the US that do it. So my day of blood results were normal, but I would like to request the test to be sent off, but I don’t know what it’s called?

Can anyone tell me the name of that test?

Also if my day of blood test was “normal” but I’m still itching, would you request the additional test?