What is C4 Complement?
Complement C4 is part of the immune system. Closely related to Component C3, C4 is a genetic element coded during the earliest stages of life. If a patient suffers from certain types of recurring infections, inflammation or edema, C3 and C4 testing can determine if there is an underlying immune system problem. Complement blood tests can also be used to stage certain conditions (acute, chronic, etc).

Due to the fact that C4 Complement is genetically coded, there are situations where levels are consistently lower than normal. Recurrent infections can be a sign of a hereditary disorder.

Normal Value Range

  • Negative Pregnancy Adult: 16 to 47 mg/dL or 0.16 to 0.47 g/L
  • Pregnancy Trimester One: 9 to 45 mg/dL or 0.09 to 0.45 g/L
  • Pregnancy Trimester Two: 10 to 42 mg/dL or 0.10 to 0.42 g/L
  • Pregnancy Trimester Three: 17 to 37 mg/dL or 0.17 to 0.37 g/L

Low C4 levels have been measured in women with lupus nephritis, C4 deficiency (hereditary), infancy, lupus erythematosus (systemic), angioneurotic edema (hereditary) or glomerulonephritis.

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