Complement C3 Test (2024)

An essential and abundant protein of the human body’s immune system, the complement component 3 is more commonly known as C3. This protein forms a part of the complement system that becomes the first line of defence against germs and viruses when the body is under attack due to an illness. The complement C3 blood test measures the activity of this protein and compares it to other components in the complement system.

A doctor can diagnose a condition such as an infection, a disease, or an autoimmune disorder, monitor a patient’s existing condition, and keep track of its progress with the test results.

What is the complement C3 used for?

The complement C3 test measures the activity of proteins that help boost the immune system in the body. Anyone with a deficiency of this protein is more likely to develop certain infections or diseases. As an inflammatory marker, this test indicates chronic bacterial or fungal infections, parasitic infections, oedema or swelling, and symptoms of autoimmune disorders.

Understanding the test results of the complement C3 Test

Test results depend on numerous factors ranging from age, sex, existing conditions, and medical history. 88 to 201 milligrams per deciliter (mg/dL) or 0.88 to 2.01 grams per litre is considered the normal range. Elevated or lower complement C3 levels could be signs of an underlying condition that a doctor can diagnose.

Complement C3 Test (1)

Frequently Asked Questions:

1. Why do I need the complement C3 test?

A doctor may recommend the complement C3 test to diagnose an infection or monitor an autoimmune disorder when the immune system is malfunctioning. When a patient shows any symptoms of an infection, lupus, kidney or liver conditions, hereditary autoimmune conditions, or even gastrointestinal diseases, it may result in altered C3 protein levels in the body.

2. What happens during a complement C3 test?

During this test, a healthcare professional draws blood from the vein in the arm. After applying an antiseptic, an elastic is wrapped on the upper arm resulting in better blood flow. After they draw blood, the punctured area is covered with a bandage. Blood is collected in a tube and sent for evaluation to a laboratory.

3. What is the normal range for the complement C3 test?

Worldwide, 88 to 201 milligrams per deciliter (mg/dL) or 0.88 to 2.01 grams per litre is the normal range for the test results. Although this range may slightly differ from laboratory to laboratory, it is best advised to consult with a doctor to understand the specific meaning of the test results.

4. What does it mean if your complement C3 is high?

Higher-than-normal or elevated C3 levels indicate that the immune system is active right after an infection or injury. Higher levels could also indicate complex conditions such as diabetes, heart attack, cancer, leukaemia, or ulcerative colitis. If a patient is already under treatment for lupus, higher C3 protein levels usually indicate that the treatment is working.

5. What causes lower C3 levels?

Lower-than-normal C3 levels indicate a range of conditions in a patient. It could be a sign of autoimmune conditions such as lupus or Crohn’s disease, cirrhosis, bacterial infection, malnutrition, hepatitis, hereditary angioedema, chronic kidney or liver conditions, rare inherited complement deficiencies, or even organ rejection. It is advisable to seek a doctor’s professional opinion.

6. What does the C3 complement test for?

The complement component 3 test helps a doctor better understand how a patient’s immune system is working at the moment. By understanding the amount of C3 proteins in the body as compared to other components in the complement system, a doctor can diagnose, monitor, and track certain infections, immune deficiencies, or autoimmune disorders in the patient’s body.

7. Are there any preparations needed before the test?

There are no preparations needed for this test. It is a simple procedure of a healthcare professional drawing blood from the vein at the back of the hand. During needle insertion, some people feel a sting or prick. While there are no side effects of having blood drawn, minor risks include excessive bleeding or lightheadedness.

8. Why is C3 low in lupus?

When a patient is diagnosed with lupus (an autoimmune condition), his/her body suffers from an impaired immune system response. The clear indicator of this is lower C3 and C4 levels in the body. In fact, with lupus, the total complement level in the body is lower-than-normal. The complement C3 test is one of the many tests used to diagnose this condition.

9. What is a complement C3 deficiency?

Complement component 3 (C3) deficiency is a condition that affects C3, the most important and abundant protein in the complement system. This condition is characterised by lower C3 levels that can be either inherited or acquired. Individuals with C3 deficiency are more prone to severe, recurrent infections caused by gram-negative and gram-positive bacteria.

Complement C3 Test (2024)

FAQs

What is a C3 complement test for? ›

A C3 complement blood test gives your healthcare provider information about your immune system. It shows how parts of your immune system are responding to harmful substances. This test can help your healthcare provider diagnose autoimmune disorders (like lupus), as well as other conditions.

Is C3 high or low in lupus? ›

In certain diseases, both components are low. In other diseases, only one component is low. In lupus, both C3 and C4 levels are usually low.

What does it mean when your C3 is high? ›

High C3 complement levels indicate inflammation in the body. The inflammation could be due to ulcerative colitis or other acute diseases like sarcoma, leukemia, or Hodgkin's Lymphoma. These are all different types of cancer. However, increased levels of C3 are not the main indication of cancer.

Is C3 a tumor marker? ›

Complement C3 may be used as a marker for the diagnosis of early-stage PC, while complement C4b1 and apoE are closely correlated with tumor development, reflecting the biological behavior of PC, and thus may be used as diagnostic markers of advanced PC.

What autoimmune disease is complement C3? ›

C3 and C4 are the most commonly measured complement components. A complement test may be used to monitor people with an autoimmune disorder. It is done to see if treatment for their condition is working. When the complement system is turned on during inflammation, levels of complement proteins may go down.

What are the symptoms of complement C3 deficiency? ›

Recurrent fever
  • Abnormality of metabolism/homeostasis. Recurrent fever.
  • Abnormality of the genitourinary system. Nephrotic syndrome. Renal insufficiency.
  • Abnormality of the immune system. Decreased circulating complement C3 concentration. ...
  • Abnormality of the respiratory system. Recurrent pneumonia.

Is C3 elevated in rheumatoid arthritis? ›

The presence of high levels of C3 in RA patients may reflect a pro-inflammatory status and represent a negative prognostic factor for anti-TNF therapy. Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory disease affecting primarily the joints and resembling the features of autoimmunity.

What labs are abnormal with lupus? ›

Complete blood count.

This test measures the number of red blood cells, white blood cells and platelets as well as the amount of hemoglobin, a protein in red blood cells. Results may indicate you have anemia, which commonly occurs in lupus. A low white blood cell or platelet count may occur in lupus as well.

What number is positive for lupus? ›

The initial requirement of the criteria for lupus diagnosis is a positive ANA test with a titer of at least 80. The numerical value of the titer refers to the ratio of blood serum being evaluated to a dilution agent.

Is C3 high with MS? ›

Levels of C3 in cerebrospinal fluid are increased in patients with MS and correlate with MRI lesions, clinical disability and levels of NFL.

Does C3 trigger inflammation? ›

Furthermore, activation of the C3 receptors (C3R) on the cell membrane, including C3a and C3b receptors (C3aR and CR1), is linked to regulation of the inflammatory response within various cells. C3aR activation amplifies the MAPK signaling pathway, leading to enhanced expression of proinflammatory cytokines.

What part of the body does C3 affect? ›

They stimulate muscle movement in your neck, shoulder, arm and hand, and provide sensation. Cervical nerves C1, C2 and C3 control your forward, backward and side head and neck movements. The C2 nerve provides sensation to the upper area of your head; C3 gives sensation to the side of your face and back of your head.

What disease can cause a high complement level? ›

If your results show increased levels or activity of complement proteins, it may mean that your body has acute or chronic inflammation. Increased levels may be a sign of the following conditions: Certain types of cancer, such as leukemia or non-Hodgkin lymphoma.

What is C3 oncology? ›

An admission to C3 is usually to manage uncontrolled pain and symptoms related to cancer. Stays on C3 typically last less than 1 week. Because of this, planning for discharge begins shortly after you arrive on. the unit. “ Discharge” is the time you leave the hospital and return home or.

What does C3 stand for? ›

The acronym for military communications has morphed over the years from C2 (command and control) to C3 (command, control, and communications) to C4I (add computers and intelligence).

What is the function of C3 complement? ›

Complement Component C3 is a large protein that plays a central role in the innate immune system by detecting and clearing potential pathogens in association with other complement proteins.

What is C3 complement kidney disease? ›

The C3 glomerulopathies are a group of rare kidney diseases characterized by complement dysregulation occurring in the fluid phase and in the glomerular microenvironment, which results in prominent complement C3 deposition in kidney biopsy samples.

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