C3 and C4 are parts of the complement immune system. The immune system is sort of complicated--- :-D If they are low it could indicate lupus or other auto-immune diseases. And my doctor checks mine every other month---as an indicator for how my disease is doing. The lower, the worser.

Anti double-stranded DNA is the anti DNA. It is an antibody specifically targeted to DNA. Its more specific for lupus if it is high.

There are two different methods it can be checked for--EIA and RIA. Usually the RIA is done--but from my understanding the EIA is more specific and accurate. When my RIA came back high, I did ask my rheumy to recheck with the EIA--it was still positive. I really could not believe that I had lupus.

Strongly positive anti DSDNA points to the possibility of kidney involvement down the road.

Thanks Surferchica, you helped me understand these results much better.

If C4 (compliment 4) is low it means there is inflamation going on or auto immune activity. It mostly occurs in lupus (low c4). I only know this because my c4 was very low which lead my rheumy to start me on steroids and then MTX. You can still have lupus and not have a positive antidsdna test. But, if your C4 is low then you should be starting treatment to help control your immune system. My C4 went up after being on steroids for 3 weeks so my rheumy knew the meds were working. All the tests can be very confusing and not all are positive in order to have lupus. Some of them are just more specific for lupus then an undifferentiated mixed connective tissue disease which is non-specific really but treated similar to lupus.

regarding what constitutes lupus---4 or more of the 11 criteria--occurring at the same time or individually over the course of time.

Specific antibodies such as DS antiDNA are listed as one of the possible 11 choices.

http://www.lupusresearchinstitute.org/lupus/lupus_diagnosis

I converted to a positive anti-DS DNA about 2 years ago. My doctor reviewed the list of possible symptoms with me and said---you have lupus. Prior to that, she said I had primary Sjogrens Syndrome.....and again now she says maybe just undifferentiated connective tissue. And my internist was sure I had mixed connective tissue.

I can only say, it is confusing!!

It is soooo confusing. Lupus is a confusing disease with so many symptoms and everyone who has it, it effects differently. I have like 7 of the 11 criteria. I do not have ds dna positive it was once but then when tested again was normal so I am not including that. LOL! I wish you all the best. Gentle hugs.