HealthTap Online Primary Care Doctors Accepting New Patients
Book a video visit
HealthTap
Telehealth
A member asked:

Dx sle. my c3 is almost always low but my c4 is always normal. have read sle has both low. alternative pathway? normal for lupus or misdiagnosis?

A doctor has provided 1 answer

Not unusual: C3 and C4 by themselves have limited value so i would not worry about your levels. If you have new onset renal insufficiency, protein in the urine and an active urine sediment then you have an issue. A low C3 by itself is not an issue.

Answered 2/13/2015

4.5k views

Thank

Related Questions

A member asked:

Thrombin 14.5,PT 22.7,APTT 79 all prolonged. APTT mix not corrected, CH50-low @22, C4 norm, C3 low. SLE pt. Lab says other results prove it is not lupus anticoagulant. What else could cause this? C3 almost always low,C4 never low. Creatnine 1.4.

A doctor has provided 1 answer

A member asked:

I'm very active, exercise daily. I'm always hydrated &get electrolytes but some days I get crashing disabling & can't even do things like grocery shop & have to sleep the day to feel better. I do have lupus but c3, c4, sed normal. Get heart checked?

A doctor has provided 1 answer

A member asked:

Is it possible to have lupus flare and always have normal c3,c4, normal CRP and sed rate no greater than 26?

A doctor has provided 1 answer

A member asked:

Does c3 & c4 have to be low to indicate lupus. My c3 was the only one low. I also had positive ana & I had more blood work done, but not back yet.

A doctor has provided 1 answer

A member asked:

What is likely to be the cause of an elevated CH50 but normal C3 & C4? My PCP tested me for lupus due to my chronic migraines & hypothyroidism...

2 doctors weighed in across 2 answers

Sponsored Content
HealthTap Medical Group does not endorse products or services. Sponsored content revenues support our mission to make health information free and accessible to all.Learn more

People also searched for:

I have a lupus overlap. My C3/C4 have always been low, but this month C4 is at its lowest while C3 is a low normal. Why would it increase? ESR is up.
Anti ds DNA ranging 24-34, low platelets 133k, low c3, normal C4 but no physical symptoms. Dr says not lupus, but what would cause it?
Complement C3 and C4 tests done 3 times due to lupus symptoms. C3 always normal but C4 borderline low twice, now normal. is this a deficiency?
Have lupus & recent C3 & C4 were normal. Rheumatologist told me lupus is stable &then said not active. However WBC still was low &malar rash from sun w/flare few months ago.Does "not active" mean complete remission & I should have NO symptoms at all?
I have lupus sle and my C3 and C4 is low .. Can this affect me ttc?

Telemedicine

Primary Care
Manage Your Conditions
Women's Health
Children's Health
Men's Health
Senior Health
Wellness, Prevention & Lifestyle
Sexual Health
Mental & Behavioral Health
Travel Medicine
Urgent Care
Ask your question
Didn't find what you're looking for?

90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more.

Ask your question

More of what we treat

Allergies
Antibiotics
Asthma
High Blood Pressure
Prescriptions
Type 2 Diabetes
Content on HealthTap (including answers) should not be used for medical advice, diagnosis, or treatment, and interactions on HealthTap do not create a doctor-patient relationship. Never disregard or delay professional medical advice in person because of anything on HealthTap. Call your doctor or 911 if you think you may have a medical emergency.
HealthTap
HIPAA logo
HIPAASecure
Soc 2 Type 2 logo
SOC 2 Type 2Certified
JCAHO Accredited
JCAHOAccredited
Member App

Download HealthTap

Video visit and message your doctor

Member App QR Code
Play Store Member LinkApp Store Member Link

Questions?

+1 (888) 828-0841support@healthtap.com
LinkedInTwitter
HomeTermsPrivacyCookiesDMCAHealth TopicsDoctors DirectoryDoctor Q&A by Specialty
Copyright 2026 HealthTap, Inc.