Emerging Assays at DRG

Blastocystis hominis and Candida species detection (15th October 2014)
Blastocystis hominis is a parasite commonly found in the GI tract. Infection of blastocystis hominis
(blastocystosis) can be characterized by diarrhea, nausea, cramps, bloating, gas, weight loss, and
fatigue. Infection often clears on its own in healthy adults but prolonged infection or patients
with symptoms lasting longer than three days may require medication to clear the infection.
Candida albicans and Candida tropicalis are yeast constituents of the normal human GI flora,
however, candida overgrowth (candidosis) can occur in immunocompromised patients and result
in gastritis. Prolonged candida overgrowth can lead to leaky gut syndrome when the yeast
hyphae penetrate the gut wall resulting in more systemic infections.
DRG Laboratory will be adding these two targets (Blastocystis hominis and Candida) to the
current GI Pathogens Plus Profile. This non-invasive stool assay will allow for specific and sensitive
detection of two important opportunistic pathogens.
Semi-quantification of Helicobacter pylori in stool (1st November 2014)
Helicobacter pylori (H. pylori) is an etiological agent of peptic ulcer disease (PUD), chronic
gastritis, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. H.
pylori is most commonly associated with gastric epithelial cells and detectable in biopsy tissues.
DRG offers quantification of H. pylori in stool, as well as qualitative detection of virulence factors
and antibiotic resistance. This assay allows for sensitive and specific detection of H. pylori using
non-invasive sampling. This semi-quantitative assay is more sensitive to low level H. pylori
infection compared to the H. pylori stool antigen ELISA that is currently used as the gold standard.
With this assay, pathogen clearance can be accurately measured over treatment time to
determine efficacy of treatment regimes.
GI Health Marker – Elastase 1 (1st November 2014)
Elastase 1 is secreted by the pancreas and remains undigested during intestinal transit. During
decreased pancreatic function or pancreatic inflammation, the level of fecal elastase decreases.
Prolonged low levels of elastase are indicative of exocrine insufficiency often associated with
chronic pancreatitis and pancreatic cancer. This addition to the DRG Laboratory GI Health Marker
test allows for sensitive and specific quantification of fecal elastase to monitor a patient’s
pancreatic function.
GI Health Marker – Secretory IgA1 and IgA2 (1st November 2014)
Secretory IgA (sIgA) is secreted by plasma cells located in the lamina propia of mucosal
membranes and is detectable in various bodily fluids including gastrointestinal secretions. The
function of sIgA is to protect the intestinal epithelium from enteric pathogens and maintain
intestinal homeostatsis. Increased levels of sIgA are associated with acute GI infections while
decreased levels are indicative of either chronic infection or IgA deficiencies. Total sIgA is
composed of two homodimers, either IgA1 or IgA2. These two proteins differ mainly in
distribution of the mucosal sites. IgA1 secreting cells are found in respiratory and upper GI tract
while IgA2 secreting cells predominate the lower GI tract. The new DRG Laboratory GI Health
Marker assay will quantitatively differentiate between IgA1 and IgA2 allowing physicians to
diagnose upper and lower GI infections.
Helicobacter pylori stool immunoglobin G (IgG) assay (12/1/2014)
H. pylori clearance is often difficult due to antibiotic resistance of the pathogen, patient noncompliance, and the inability to collect follow up biopsy tissue for validation of pathogen
clearence. The H. pylori stool Ig assay quantifies the amount of H. pylori-reactive antibody (IgG)
present in a patient’s stool sample. High levels of H. pylori-reactive antibody is indicative of an
active infection while low levels of H. pylori-reactive antibody is indicative of a non-active
infection or pathogen clearance. Disclaimer : Although initial concentrations of anti-H. pylori
reactive antibodies does not correlate with disease severity, studies have confirmed that
successful treatment can be monitored by studying the fall in serum levels of IgG over a period of
up to one year after the start of therapy. A decrease in anti-H. pylori IgG antibodies after three
months is strong evidence of successful treatment.
This is a non-invasive test to detect a patient’s immunological response to an H. pylori in the
upper and/or lower GI tract. This test will also be able to determine pathogen clearance following
an upper GI only H. pylori infection.
Anti-Gliadin IgA/IgG and Tissue Transglutaminase test (1st January 2015)
Celiac disease (CD), or gluten-sensitive enteropathy, is an immune mediated inflammatory
process of the small intestine mucosa that occurs following ingestion of gluten present in wheat,
rye, and barley. CD can manifest as gastritis with abdominal pain, diarrhea, or constipation, or as
systemic symptoms, such as anemia, chronic fatigue, fetal loss, failure to grow, and other chronic
manifestations. Current diagnosis of CD relays on serological quantification of tissue
transglutaminase (tTG) antibodies, either IgA or IgG prior to jejuanl biopsy to detect villous
atrophy.
DRG Laboratory currently quantifies anti-gliadin IgA present in patient’s stool samples as an
indicator of wheat sensitivity. A full celiac disease panel is under development. This new panel
will quantify levels of tTG and anti-gliadin antibodies, both IgA and IgG isotypes. These additional
markers will allow for non-invasive sensitive screening to identify patients with a high probability
of having celiac disease prior to referral for invasive and expensive biopsy procedures.

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