Common Tests or Labs to Diagnose Irritable Bowel Syndrome

There are no definitive tests for Irritable Bowel Syndrome.

The standard questionnaire in history taking involves the Rome III Criteria. These criteria involve at least 3 days/month of symptoms and breaks down the frequency and intensity of:

  • Recurrent abdominal pain or discomfort
  • Functional (ongoing) bloating
  • Constipation
  • Diarrhea
  • Unknown disorder symptoms

In patients over the age of 50 who are developing symptoms for the first time, it is prudent to rule out any other medical causes by undergoing the following tests.

 

Test Why Test? What Happens? Normal Result
Complete Blood Count (CBC) WBC elevation denotes inflammation

Anemia from lowered RBC, hemoglobin and hematocrit suggests a loss of blood

After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis.

The tourniquet is then removed and a pressure bandaid is applied.

 

WBC=4.5-11

 

RBC

Male 4.5-5.3

Female=4.1-5.1

 

Hemoglobin

Male= 13-16

Female= 12-16

 

Hematocrit

Male=37-49%

Female=36-46%

Stool Analysis Looks for:

* Blood

* Parasites (Giardia lamblia, pinworms)

* Bacteria

* Fungus

* Virus

Stool specimen is inserted into a sterile cup that is provided to you and sent to the laboratory for analysis No blood or abnormal organisms are found.
Colonoscopy Looks for:

* Growths

* Tumors

* Ulcer

* Strictures of the large intestine

After lying on an exam table, sedation is given by IV in your arm. The doctor then passes a long, flexible scope with light attached to a video monitor up from your rectum to view the entire large intestine. When done the instrument is removed and you are awakened. No growths, or ulcers,

Tumors or strictures seen.

Thyroid Function Tests Checks for antibodies

Scans size of gland

Tests thyroid hormone levels

For antibodies and hormone levels, a tourniquet is applied to the upper arm. The puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe which is then sent for analysis

For the thyroid scan, a small amount of radioactive iodine is taken orally which gathers within the thyroid gland. X-ray images are then taken.

A sonogram of the thyroid is performed while you are lying on the examination table. A gel is applied to the throat area and a wand emanating pulses is placed back and forth over the area. Echoes produce an image on a monitor.

 Anti-TPO antibodies are not present.

 

TSH (thyroid stimulating hormone)

.5-6uU/ml

T3 (serum triiodothyronine)

80-180 ng/dL

T4 (thyroxin)

4.6-12ug/dL

FT4I (free thyroxine Index)

.7-1.9 ng/dL

TBG (thyroid binding globulin)

12-20 ugdL

No nodules or growths are seen

Blood Tests for Celiac Disease Tests for 3 types of antibodies:

* Anti-gliadin

* Anti-tissue transglutaminase

* Endomysial

After a tourniquet is applied to the upper arm, the puncture site of skin is swabbed with alcohol and a needle punctures the skin, entering a vein. Blood is drawn into a syringe for analysis.

The tourniquet is then removed and a pressure Band-Aid is applied.

Antibodies are normally absent
Small Intestinal Biopsy The pathologist searches microscopically for loss of villi and increased white blood cells which are characteristic of celiac sprue You lie on an examination table and sedation is given.

The doctor inserts a long, flexible viewing endoscope through the mouth and into the duodenum. A long biopsy tool is passed through a channel in the endoscope to take snips of the duodenal lining. .

After the biopsies are done, visualization ensures no acute bleeding. The instruments are withdrawn and the test is finished.

Normal pink lining of the intestines with no growth, pouching or strictures.

Normal amount of villi and white blood cells are seen on microscopic exam.

 

Written by Barbara Hales, MD

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