Complement C4 Test:
Complement C4 is an integral part of the complement system which is a vital part of our immune system. Complement C4 is involved in eliminating certain infection. The complement C4 test measures the amount of this component in blood. The test is often ordered when signs and symptoms of an autoimmune disease are observed.
Factors involved to understand the normal range of Complement C4 levels:
Normal range for complement C4 in blood is 16-48 mg/dL. Normal results may vary from laboratory to laboratory.
Higher than normal levels of complement C4 are generally during chronic or acute inflammation. It may also be a sign of cancer or ulcerative colitis. Increased levels of complement C4 indicate various conditions such as:
Higher concentrations of complement C4 may not exactly indicate the condition present but it helps the doctor to determine involvement of immune system with the condition.
Inflammatory conditions lead to an increase in C4 levels in the blood. The levels of C4 rise with low-grade inflammation. Inflammatory conditions that cause an increase in C4 levels include:
Levels of C4 are also seen to be elevated during pregnancy and due to use of certain drugs such as cimetidine.
Lower than normal levels of complement C4 are associated with autoimmune disorders such as systemic lupus erythematosus. They could also indicate a number conditions such as:
Lower C4 levels may also be a sign of alcoholic liver disease. If C4 levels are lower because of acute or chronic infections, treatment of underlying condition brings the C4 levels back to normal.
Several conditions cause a decrease in the complement C4 levels. These include:
Autoimmune diseases involve a lot of factors and may vary from one person to another. It is important to work with your healthcare provider to treat the underlying conditions that may cause your complement levels to be abnormal.
To prevent decrease in the levels of C4, it is advised to refrain from over eating and reducing intake of fatty foods. Supplements such as mangosteen are thought to boost up C4 levels. Avoiding cannabis, exposure to heavy metals and allergens is recommended to avoid C4 levels from going lower than normal.
Certain lifestyle and dietary changes can help reduce the risk of chronic inflammation and prevent the elevation in C4 levels. These changes may include losing weight, exercises, getting enough sleep, reducing stress, consuming an anti-inflammatory diet, etc.
Most people don’t experience any serious side effects with blood tests. If complications arise, although they are very rare, they include:
They do not require any treatment and may gradually fade on their own.
Along with complement C4 test, a total complement activity test or CH50 test is recommended. The test estimates all the nine components of the complement system. A separate complement C3 test is also ordered along with complement C4 test. This is because in certain conditions, like lupus, both the components are low.
Additional testing is advised when the doctor suspects the presence of an autoimmune disease. If the doctor suspects lupus, additional blood tests are ordered to check the functioning of the immune system. These tests include measurement of antibodies in blood, sedimentation rate or ESR, C-reactive protein test, and kidney and liver function test panels.
A follow up testing or treatment is recommended based on the results of these tests.
The test requires no special preparation. Complement C4 test is often ordered when the doctor suspects signs and symptoms of autoimmune diseases. The complement activity is measured to determine the severity of the disorder or to check if the treatment is working.
Test results may vary according to the underlying conditions and discussing with your doctor about what the results may mean for you is important. Your doctor may recommend other tests to confirm the diagnosis of suspected autoimmune disorders.
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