Yeah, false negatives are fairly common, because you don't always pass the pathogens with each bowel movement. My GI had me submit two different samples, I think for Giardia, because it doesn't always pass. Both were negative.
Symptoms began in November 2008, ~4 weeks after giving birth to my son.
Eased for ~3 weeks in December, possibly b/c of probiotic use?
Returned in January 2009 (with a vengeance), diagnosed with pancolitis on January 30.
Currently taking Asacol (400mg 4 pills 3x daily), Rowasa nightly,
40mg 30mg 20mg 15mg 10mg of Prednisone (quick taper), Culturelle probiotic, and Zoloft (25 mg).