A new report shows the brains of autistic children, who suffer from the disorder tied to a combination of contributing factors from genes to the environment, have differences in regions that develop during the mother's second trimester of pregnancy.
Complement component 4 is a blood test that measures the activity of a certain protein that is part of the complement system. The complement system is a group of proteins that move freely through your bloodstream.
Highlights. 1  T4 is a hormone that plays a role in several body functions, including growth and metabolism. 2  There are two kinds of T4 tests: a total T4 test and a free T4 test. 3  A number of drugs can interfere with your T4 levels, so tell your doctor what medications youâre taking before a T4 test.