I think you might want to ask the folks in the crohns forum or ulcerative colitis forum. Normally in like over 95% of lupus patient do not get blood in their stools.
We can at times have GI issues, but in the 26 years that I've had lupus I've never had blood in my stool, nor have I talked to anyone who has.
Sorry, I can't be of any help to you.
DX- RA, Lupus, Fibro, LGL Leukemia, Obstructive & Central Sleep Apnea, Pulmonary Hypertension, Bells Palsy, Gastroparsis, Blood Clots, Glaucoma, Chronic Pericarditis & Pleurisy, Severe Anemia. Way to many medications to list.