"I had various stool samples taken by local hospital etc over the years and they found nothing. *Parascope did though."
Posted by Ian on the Parasites and Digestive Illness message board.
Ian was diagnosed by Parascope, a private UK lab, with both B.hominis & D.fragilis.
June 02

Studies show that detection of D.fragilis & Blasto. hominis increases significantly when stool samples are collected in liquid fixative. The fixative prevents morphological changes to the parasite as the parasite begins to die. This disintegration is largely prevented by the fixative, which keeps the parasite intact for more accurate lab identification.

Published medical literature explicity states that the likelihood of parasites being detected in a single sample is less than fifty percent (B.H.Kean, M.D., & C.L.Malloch, MD. Am.J.of Dig.Dis. Vol 11, N o.9, 1966). Collection of a single stool sample in patients suffering digestive disorders has been standard medical practice for decades, and has contributed greatly to the underdiagnoses of these parasites.

Reports from Canada, Australia, the UK and other European countries to this site show that some labs will report the presence of Blastocystis hominis only when requested by the treating physician.

Other reports show that labs do not report its presence if Blasto. is found in low numbers. However, published studies show that the shedding pattern of parasites is inconsistent:

"The study shows that there is marked fluctuation in the shedding of the parasite from day to day, varying from as high as 17 to 0 per x40 microscopic field.
The cystic stages when estimated in 8 Blastocystis-infected individuals ranged from as high as 7.4x10(5) cysts per gram of stool to 0.
(Parasitol Res. Vennila GD, et al. 1999 Feb;85(2):162-4)

Labs which specialise in finding Dientamoeba fragilis and Blastocystis hominis have been criticised by some specialists for "over reporting" these parasites.

CLICK HERE FOR INFORMATION ABOUT SPECIFIC TESTING FOR D.FRAGILIS
CLICK HERE FOR INFORMATION ABOUT SPECIFIC TESTING FOR B.HOMINIS

OPTIMISING YOUR STOOL TEST RESULTS:
Parasites adhere to the bowel wall. Submitting purged samples increases the chance of detection. Purging prior to taking medication can help reduce the infection.
Purging info. is here

Testing for other parasites:

Both Dientamoeba fragilis and Blastocytis hominis inhabit the large intestine, cecum and have been found in the lower part of the small intestine, whilst the parasites Giardia and Entamoeba histolytica colonise the small intestine. Colonisation higher up the bowel can make diagnoses even more difficult.

To overcome this problem a chemical test called ELISA (enzyme-linked immunosorbent assay) is considered "gold standard" for diagnosing Entamoeba histolytica, Giardia and Cryptosporidium. ELISA depends on detection of parasite antigens, instead of a skilled lab technician identifying the parasite.

ELISA is usually performed on fresh stools and considered 90%+ accurate. Most standard labs will perform this test on request.

A salivary test which detects antibodies is also available from Diagnos-Techs, Inc. The contact details for this and other labs using these testing methods are on the "where to find help" page of this site. Salivary testing is another controversial area, and reports to this site indicate that that some doctors do not accept the results of salivary tests, preferring to look elsewhere for their patients causes, or diagnose Irritable Bowel Syndrome. Example here.