Vitamin B12 level is declining

I was diagnosed with vitamin B12 deficiency in Oct 2006.  My B12 level was undectable at that time.  It was eventually determined that my body no longer produces intrinsic factor.  Since Oct 2006 I have received intramuscular injections (1000mcg of B12) every other week.  My level did rise to 360 pg in Jan 2007, but since then my results have been:  349 pg in Feb 2007 and 278 pg in May 2007.  Any ideas why my B12 level is declining even though I continue to receive injections every other week?

[barn babe]

What does your doctor say about this? Have you asked her why your levels are declining?   Really, we are a bunch of internet yahoos and this is beyond the expertise of most people posting here. Good luck, though.