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Complement C4

Item# LC001834


Complement C4

Item# LC001834


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  • Complement C4
  • Item Catalog Number: LC001834

The complement system is a group of proteins that are important in your defense against infection and play a role in the development of inflammation.

There are nine major complement proteins called C1 through C9. These various components travel through your blood stream searching for foreign invaders such as bacteria or viruses. When this happens, the complement system is activated and works as a cascading event like the falling of a row of dominoes. Most of the time the outcome of compliment activation is favorable; the "foreign invader" is removed with no damage to cells or tissue. But in some people, the compliment system activation becomes uncontrolled or certain components may be deficient causing autoimmune disease or the risk of recurrent mild or serious bacterial infections.

This blood test measures component 4 (C4) of the complement system. Deficiency of C4 is closely linked to development of autoimmune diseases such as Lupus and rheumatoid arthritis.1


Fasting is not required. Take all medications as prescribed.


For those following Dr. Shoemaker’s mold testing, this is testing C4 (β1E Globulin), NOT C4a. He suggests using specifically Quest labs for C4a.


  1. Accessed March 2015

The laboratory services are for informational purposes only. It is not the intention of National Diagnostics, Inc and Life Extension to provide specific medical advice but rather to provide users with information to better understand their health. Specific medical advice including diagnosis and treatment will not be provided. Always seek the advice of a trained health professional for medical advice, diagnosis or treatment.

Both the physician and the testing laboratory are independent contractors with whom National Diagnostics, Inc makes arrangements for your blood tests. Neither National Diagnostics, Inc or Life Extension will be liable for any acts or omissions of the physician, the testing laboratory, or their agents or employees.


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