MyLupusTeam

Are your C3 and C4 complement levels within a normal range, and what do they mean for lupus?

Your C3 level of 136 and C4 level of 20 both fall within the generally accepted normal ranges:

- C3 normal range: 90–180 mg/dL
- C4 normal range: 16–47 mg/dL

This is actually good news! Both levels look normal right now.

In lupus Show Full Answer

Are your C3 and C4 complement levels within a normal range, and what do they mean for lupus?

Your C3 level of 136 and C4 level of 20 both fall within the generally accepted normal ranges:

- C3 normal range: 90–180 mg/dL
- C4 normal range: 16–47 mg/dL

This is actually good news! Both levels look normal right now.

In lupus, complement proteins like C3 and C4 are important markers. When lupus is active, the immune system "uses up" these proteins to fight inflammation, causing levels to drop below normal. Low complement levels can signal a flare.

Since your numbers appear normal, it may suggest your lupus is not currently in an active flare — but always discuss these results with your rheumatologist, as they'll interpret them alongside your full picture (symptoms, other labs, etc.).

A few things worth knowing:

- Levels can change over time, so regular monitoring matters
- Some people with lupus naturally run lower complement levels even when stable
- Trends over time are often more meaningful than a single result

 AI-generated responses are not a substitute for medical advice. These services are not intended to diagnose, treat, or cure any condition or disease. Always ask your doctor about specific health concerns.

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