Sigmoidoscopy alone is not enough, it must be sigmoidscope with doctor truly knowing what parasites they are looking for, knowing importance of preparing the fresh sample while still fresh, typically will need their own lab ....
for example sigmoidscope with a gastro doctor not trained very well in parasitology diagnostics are typically doing sigmoidscope just to look for inflammation, polyps, cancer etc...I know several gastro doctors do sigmoidscope without at same time doing any proper testing for parasites...
so not enough to just call up a pastor doctor asking if he do sigmoidsope...it must be a doctor truly knowing parasites and also practicing what they know...