C1q Deficiency Blood Test

What is C1q Deficiency?

C1q deficiency is a rare inherited immunodeficiency disorder where the body does not produce sufficient amounts of the C1q protein, a critical component of the complement system. It is caused by genetic mutations that prevent the production of functional C1q protein, leading to impaired immune function and increased susceptibility to infections and autoimmune diseases. The Complement Component C1q blood test is the most important test for diagnosis because it directly measures C1q protein levels in the blood.

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What causes C1q deficiency?

C1q deficiency is caused by inherited genetic mutations that prevent the body from producing adequate amounts of the C1q protein. These mutations are typically passed down in an autosomal recessive pattern, meaning both parents must carry the defective gene for a child to develop the condition. The C1q protein is the first component of the classical complement pathway, and without it, the entire immune cascade is disrupted, leading to severe immune dysfunction.

What is the best test for C1q deficiency?

The Complement Component C1q blood test is the most important test for C1q deficiency because it directly measures the levels of C1q protein in your blood. This specialized test is essential for confirming the diagnosis, as low or absent C1q levels definitively indicate the deficiency. The test helps doctors understand why you might be experiencing recurrent infections or autoimmune symptoms, as impaired complement system activation leaves your immune system compromised. Additional complement testing may be ordered to evaluate the entire complement cascade, but the C1q test is the cornerstone of diagnosis.

When should I get tested for C1q deficiency?

You should get tested if you experience recurrent bacterial infections starting in early childhood, have been diagnosed with autoimmune conditions like lupus at a young age, or have a family history of C1q deficiency. Testing is also important if you have unexplained immune system problems, frequent skin infections, or kidney disease that doctors cannot explain through other conditions. Early diagnosis through blood testing is crucial because it allows for proper immune monitoring and preventive treatment to reduce infection risk.

What are the symptoms of C1q deficiency?
People with C1q deficiency typically experience recurrent bacterial infections, particularly affecting the skin, respiratory tract, and urinary system. Many patients develop autoimmune conditions, especially systemic lupus erythematosus (SLE), which can cause joint pain, skin rashes, and kidney inflammation. Other symptoms include fever, fatigue, unexplained inflammation, and in severe cases, glomerulonephritis (kidney disease). Symptoms often begin in early childhood and can range from mild to life-threatening depending on the severity of the deficiency.
Who is at risk for C1q deficiency?
C1q deficiency is an inherited condition that affects individuals who receive two copies of the mutated gene, one from each parent. People with a family history of the disorder are at highest risk, as are children born to parents who are both carriers of the genetic mutation. The condition is extremely rare, affecting fewer than 1 in 1 million people worldwide, but consanguineous marriages (marriages between close relatives) increase the risk of inheriting two copies of the defective gene.
What happens if C1q deficiency is left untreated?
If left untreated, C1q deficiency can lead to severe and potentially life-threatening complications. Patients face ongoing recurrent infections that can become progressively more serious, potentially leading to sepsis or organ damage. Autoimmune diseases, particularly lupus, can develop and cause progressive kidney damage, heart problems, and neurological complications. The compromised immune system makes it difficult to clear immune complexes from the body, leading to chronic inflammation and tissue damage that worsens over time without proper medical management.
Can C1q deficiency be diagnosed with a blood test?
Yes, C1q deficiency is diagnosed with a specialized blood test that measures the amount of C1q protein in your blood. The Complement Component C1q test is the definitive diagnostic tool, showing low or absent levels of this critical immune protein. Your doctor may also order additional complement tests to evaluate the entire complement system and genetic testing to identify the specific mutation causing the deficiency. Blood testing is the only reliable method to diagnose this condition, as physical examination alone cannot detect it.
How is C1q deficiency treated?
C1q deficiency is treated through preventive strategies and management of complications rather than a cure. Treatment includes prompt antibiotic therapy for infections, sometimes with prophylactic antibiotics to prevent recurrent bacterial infections. Patients with autoimmune complications receive immunosuppressive medications like corticosteroids or hydroxychloroquine to control inflammation. Regular monitoring through blood tests helps track complement levels and detect early signs of infection or autoimmune flares. Some patients may benefit from intravenous immunoglobulin (IVIG) therapy to boost immune function.
How can I prevent complications from C1q deficiency?
While you cannot prevent C1q deficiency itself, you can reduce complications through proactive health management. Stay up to date with all recommended vaccinations to prevent infections, practice excellent hygiene including frequent handwashing, and avoid exposure to people with contagious illnesses. Regular medical monitoring with blood tests helps catch problems early, and maintaining close communication with an immunologist ensures prompt treatment of infections. Eating a nutrient-rich diet, getting adequate sleep, and managing stress also support your overall immune health.
What can I do at home for C1q deficiency?
At home, focus on supporting your immune system through healthy lifestyle choices. Maintain excellent personal hygiene, avoid crowds during flu season, and keep your living environment clean to minimize infection exposure. Eat a balanced diet rich in fruits, vegetables, and lean proteins to support overall health, stay well-hydrated, and get 7-9 hours of quality sleep each night. Monitor yourself for early signs of infection like fever, unusual fatigue, or skin changes, and contact your doctor immediately if symptoms appear. Keep a health journal to track symptoms and share with your medical team.
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Is it possible to make changes to my lab order if I made a mistake with the name, date of birth, or any other details?
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Just reach out to us via text at 754-799-7833 or shoot us an email at support@privatemdlabs.com. Remember to include your order number and let us know the correct information you’d like to update. Our awesome team will jump right in and make sure everything is sorted out and accurate for you.

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If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com and we'll gladly help you.
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Complement Component C1q
Google reviews 505 reviews
$427 $333
What's included
Fast & easy, results by email & SMS
No need to visit a doctor
Private & confidential
No insurance needed
Results explained
No extra fees paid at the lab

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