What is Complement C3?
The complement system is a cascade of the activation of several proteins to fight against infections and to keep the body healthy. Complement C3 is an essential protein of this cascade that functions to remove the damaged cells from the body, clear the pathogens, and fight against infection. This protein is primarily produced in the liver and is one of the most abundant complement proteins in the bloodstream as it is vital in classical and alternative pathways. The primary function of the C3 complement is the activation of the complement system. After the activation, the C3 splits into two components C3a and C3b. C3a is responsible for triggering the inflammation as it works as an anaphylatoxin whereas C3b is significant in the opsonization i.e. labeling the pathogens so that the white blood cells can easily target them.
The complement C3 test is conducted to measure the levels of the protein complement C3 in the bloodstream. Abnormal levels are suggestive of underlying immune dysfunction, autoimmune disorders, or rheumatoid arthritis.
How is the Test Performed?
The complement C3 test is a simple, minimally invasive blood test:
Preparation
- No dietary restrictions are given before the test.
- Inform your doctor about the medication you are taking particularly steroids and immunosuppressant.
Collection
- The blood sample is collected by a technician using a needle.
Laboratory Analysis
- The sample is then analyzed in the laboratory for further analysis by using techniques such as nephelometry and immunoturbidimetry.
What are the symptoms that prompt this test?
This test is recommended for individuals exhibiting the symptoms of an autoimmune disorder or other associated symptoms of complement C3 dysfunction.
Symptoms of Autoimmune Disorders
- Lasting fatigue
- Pain in the joints
- Swelling in the joints
- Butterfly-like rashes
- Kidney disorder
- Sunlight sensitivity
Recurrent Infections
- Chronic infections of the sinus and ears
- Pneumonia that occurs again and again
- Wound healing at a slow rate
Inflammatory Disorders
- Swelling and redness
- Weight gain without a known reason
- High blood pressure
- Persistent fatigue
What are Normal Ranges for This Test?
Complement C3 may fluctuate due to an ongoing infection, underlying health condition, and age of an individual, the generally accepted reference ranges are given below. The values are given in units’ milligrams per deciliter.
Adults – 90 to 180 mg/dL
Children – 80 to 170 mg/dL
Neonates – 70 to 160 mg/dL
** The values given above are for general guidelines only and may vary according to the assay of the test. **
What Happens if Test Results Show Abnormal Levels?
If the test result shows abnormal levels of C3 whether high or low, it is an indication that the person’s health is compromised and is affected by an underlying health condition. The possible health issues that a person might have due to elevated or lowered levels are mentioned below:
Low Levels of C3
Low levels are suggestive of over-activation or the deficiency of C3 caused by;
- Glomerulonephritis
- Bacterial sepsis
- Systemic lupus erythematosus
- Hereditary complementary deficiency
High Levels of C3
Associated with inflammation or metabolic conditions;
- Metabolic syndrome
- Obesity
- Chronic inflammatory disease
- Bacterial or viral infections
