Understanding Lab Tests for C1q Deficiency
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
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. This deficiency significantly impacts immune function and requires specialized blood testing for accurate diagnosis.
Recommended Test
Complement Component C1q
This specialized blood test directly measures the levels of C1q protein in the blood. Since C1q deficiency is characterized by insufficient production of this complement protein, this test is essential for confirming the diagnosis. Low or absent C1q levels indicate the deficiency, which helps explain increased susceptibility to infections and autoimmune conditions due to impaired complement system activation.
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Why Blood Testing is Essential for C1q Deficiency
Since C1q deficiency affects the complement system - a vital part of immune defense - patients may experience recurrent infections and increased risk of autoimmune diseases. Blood testing is the primary method to measure C1q levels and confirm the diagnosis, as this condition cannot be reliably identified through physical examination alone.
Understanding C1q and the Complement System
C1q is the first component of the classical complement pathway, playing a crucial role in immune surveillance and the clearance of pathogens and immune complexes. When C1q levels are deficient, the entire complement cascade is affected, leading to compromised immune responses and increased risk of both infections and autoimmune disorders.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. C1q deficiency is a complex immunological condition that requires specialized medical management. Always consult with a healthcare provider or immunologist for diagnosis and treatment.
