Irritable bowel syndrome laboratory findings
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].
OR
Laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].
OR
[Test] is usually normal among patients with [disease name].
OR
Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].
OR
There are no diagnostic laboratory findings associated with [disease name].
Laboratory Findings
- The diagnosis of IBS is based on clinical symptoms and elimination of other organic gastrointestinal diseases. This is due to lack of definitive radiologic or laboratory diagnostic tests in IBS.[1][2][3][4][5]
- If the history and physical exam are suggestive of IBS in the absence of alarm features, the following tests rule out organic causes by 97 percent:
- CBC- normal in IBS
- Occult blood test- normal in IBS
- Complete metabolic panel- normal
- ESR- normal
- Additional tests may be costly and harmful in young patients with typical IBS symtoms, in the absence of alarm features.
- To determine the aggressiveness of the diagnostic evaluation, the American Gastroenterological Association has defined certain factors that must be considered:
- Degree of psychosocial impairment
- Age and sex of the patient
- Family history of colorectal cancer
- Prior diagnostic studies
- Duration of symptoms
- Change in symptoms over time
- In patients that require aggressive diagnostic evaluation, additional diseases need to be ruled out:
- Celiac disease: Serological screening
- IBD:
- Inflammatory markers(ESR, C-reactive protein, plasma viscosity) are likely to be raised
- LFTs- decreased serum albumin
- Complete blood count shows IDA due to blood loss
- Giardiasis: prevalent in developing countries
- stool sample for microscopy
- culture with specific request to look for ova, cyst and parasites
- Other organic causes are suspected if lab investigations show the following:
- Complete blood count- evidence of anemia
- ESR raised
- Stool Volume >200–300 mL/day
- Stool content: Blood and leukocytes
This disorder should be screened for with
antiendomysial antibodies. A full blood count, renal and
liver function tests, thyroid function testing, and
investigation of stool sample for parasites all have very
low yields but are inexpensive.109
Most patients should have a complete blood count and
sigmoidoscopic examination; in addition, stool specimens should
be examined for ova and parasites in those who have diarrhea.
In patients with persistent diarrhea not responding to simple
antidiarrheal agents, a sigmoid colon biopsy should be performed
to rule out microscopic colitis.
In those age >40 years, an aircontrast
barium enema or colonoscopy should also be performed.
If the main symptoms are diarrhea and increased gas, the possibility
of lactase deficiency should be ruled out with a hydrogen breath test
or with evaluation after a 3-week lactose-free diet.
Some patients with IBS-D may have undiagnosed celiac sprue. Because the symptoms
of celiac sprue respond to a gluten-free diet, testing for celiac
sprue in IBS may prevent years of morbidity and attendant expense.
Decision-analysis studies show that serology testing for celiac sprue
in patients with IBS-D has an acceptable cost when the prevalence
of celiac sprue is >1% and is the dominant strategy when the prevalence
is >8%.
OR
- An elevated/reduced concentration of serum/blood/urinary/CSF/other [lab test] is diagnostic of [disease name].
- [Test] is usually normal among patients with [disease name].
- Laboratory findings consistent with the diagnosis of [disease name] include:
- [Abnormal test 1]
- [Abnormal test 2]
- [Abnormal test 3]
- Some patients with [disease name] may have elevated/reduced concentration of [test], which is usually suggestive of [progression/complication].
References
- ↑ Longstreth GF, Thompson WG, Chey WD, Houghton LA, Mearin F, Spiller RC (2006). "Functional bowel disorders". Gastroenterology. 130 (5): 1480–91. doi:10.1053/j.gastro.2005.11.061. PMID 16678561.
- ↑ Drossman DA, Camilleri M, Mayer EA, Whitehead WE (2002). "AGA technical review on irritable bowel syndrome". Gastroenterology. 123 (6): 2108–31. doi:10.1053/gast.2002.37095. PMID 12454866.
- ↑ Spiller R, Aziz Q, Creed F, Emmanuel A, Houghton L, Hungin P, Jones R, Kumar D, Rubin G, Trudgill N, Whorwell P (2007). "Guidelines on the irritable bowel syndrome: mechanisms and practical management". Gut. 56 (12): 1770–98. doi:10.1136/gut.2007.119446. PMC 2095723. PMID 17488783.
- ↑ Brandt LJ, Bjorkman D, Fennerty MB, Locke GR, Olden K, Peterson W, Quigley E, Schoenfeld P, Schuster M, Talley N (2002). "Systematic review on the management of irritable bowel syndrome in North America". Am. J. Gastroenterol. 97 (11 Suppl): S7–26. PMID 12425586.
- ↑ Yawn BP, Lydick E, Locke GR, Wollan PC, Bertram SL, Kurland MJ (2001). "Do published guidelines for evaluation of irritable bowel syndrome reflect practice?". BMC gastroenterology. 1: 11. PMID 11701092.