Looking for ELISA kit for proteinase 3 - Not anti-proteinase 3 antibody ELISA kit (Aug/18/2005 )

I am looking for the ELISA kit for proteinase 3, but all I found is the ELISA kit for anit-proteinase 3 antibody which is for C-ANCA. I am trying to come up with a assay by myself, but I always get a high background (od = 0.2, my highest od = 1 with about 500ng/ml of proteinase 3) and also the sensitivity is kind of low. I tried 2% BSA and 2% gelatin as blocking buffer, I also tried 5% dry milk to block, but it doesn't work well at all.
The sample I am working on is human serum. ELISA is new to me and I am kind of frustrated about this.

I am appreciate for any suggestion and help.

hi
im workin on ANCa, but m a little unsure about wat you want.......Do u want an ELISA to detect PR 3, and not anti-PR3? if you can tell me wat exactly u are workin at, maybe i can help u.....