3. Has anyone taking the traditional laboratory stool test for parasites and came back negative, but ended up having parasites?
YES! Traditional, corporate lab screenings are not very reliable.
I was infected with giardia & schistosoma in India in 2003... had suspicious symptoms, and got checked (via standard lab stool test) soon after I got back to the US. The test found the giardia but totally missed the schistoma.
Subsequent lab tests ordered by my Dr. in 2004 and 2010 came back negative for everything.
I wasn't until I collected the stool samples on the days after the full moon (suspected egg laying period)in 2014 and sent the sample to Dr. Amin's lab in Arizona was I able to understand what was causing the irritation & fatigue.