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.
The Test. Complement tests, most commonly C3 and C4, are used to determine whether deficiencies or abnormalities in the complement system are causing, or contributing to, a person's disease or condition.Total complement activity (CH50 or CH100) may be ordered to look at the integrity of the entire classical complement pathway.omplement testing may be used to: 1  Help diagnose the cause of recurrent microbial infections (such as Streptococcus pneumoniae, Neisseria meningitides, Neisseria gonorrhea), angioedema, or inflammation.