Have a symptom?
See what questions
a doctor would ask.
Symptoms » Diarrhea » Diagnostic Tests

Diagnostic Tests for Diarrhea

Diagnostic Test list for Diarrhea:

The list of diagnostic tests mentioned in various sources as used in the diagnosis of Diarrhea includes:

  • Physical examination
    • Abdominal examination for tenderness and a mass e.g. a mass in the right lower abdomen may suggest bowel cancer or diverticulitis; a mass on right, left or upper abdomen may also suggest bowel cancer; tenderness in the left lower abdomen, with or without a significant mass may suggest ulcerative colitis, diverticulitis or irritable bowel syndrome
    • Examine rectum for hemorrhoids and anal fissure that may be causing a positive occult blood test
    • Examine for signs of systemic diseases that may cause diarrhea e.g. tremor and increased heart rate of hyperthyroidism; considerable flushing of carcinoid syndrome; hyperpigmentation of the skin in Addison's disease; and dermatitis and dementia of pellagra
  • Blood tests
    • Full blood count and ESR, Electrolytes and thyroid function tests - if systemic disease is suspected to be the cause of diarrhea.
    • Salmonella antibodies - not useful in acute situation.
    • Amoeba antibodies - not useful in acute situation.
    • HIV test - if suspected on history.
    • Gastrin level - if suspect a gastrinoma (Zollinger-Ellison syndrome).
  • Stool tests
    • Test for occult blood (if positive may suggest infectious disease of the large intestine or small intestine, ulcerative colitis, bowel cancer, diverticulitis, Zollinger-Ellison syndrome)
    • Stool microscopy for ova, parasites and culture for bacteria
    • Giardia antigen
    • Clostridium difficile toxin B - if history of antibiotic use.
    • 24 hour Stool analysis of fecal fat - if steatorrhea is present (i.e. fatty, pale colored, extremely smelly stools that float in the toilet and are difficult to flush away due to excess fat in the stool).
  • Urine tests
    • 5-HIAA - if suspect Carcinoid syndrome.
  • Radiological investigations
  • Sigmoidoscopy and/or colonoscopy with or without a small bowel aspiration and biopsy - if diarrhea persists or if blood is present ( may be required to detect bowel cancer, bowel polyps, celiac disease, Giardia infection.
  • Medical history
  • Physical exam
  • Stool culture
  • Blood tests
  • Fasting tests - for various food allergies.
  • Sigmoidoscopy
  • Colonoscopy

Home Diagnostic Testing

These home medical tests may be relevant to Diarrhea causes:

Tests and diagnosis discussion for Diarrhea:

Diagnostic tests to find the cause of diarrhea include the following:

  • Medical history and physical examination. The doctor will need to know about your eating habits and medication use and will examine you for signs of illness.

  • Stool culture. Lab technicians analyze a sample of stool to check for bacteria, parasites, or other signs of disease or infection.

  • Blood tests. Blood tests can be helpful in ruling out certain diseases.

  • Fasting tests. To find out if a food intolerance or allergy is causing the diarrhea, the doctor may ask you to avoid lactose (found in milk products), carbohydrates, wheat, or other foods to see whether the diarrhea responds to a change in diet.

  • Sigmoidoscopy. For this test, the doctor uses a special instrument to look at the inside of the rectum and lower part of the colon.

  • Colonoscopy. This test is similar to sigmoidoscopy, but the doctor looks at the entire colon.
(Source: excerpt from Diarrhea: NIDDK)

Conditions listing medical symptoms: Diarrhea:

The following list of conditions have 'Diarrhea' or similar listed as a symptom in our database. This computer-generated list may be inaccurate or incomplete. Always seek prompt professional medical advice about the cause of any symptom.

Select from the following alphabetical view of conditions which include a symptom of Diarrhea or choose View All.

View All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z #

Conditions listing medical complications: Diarrhea:

The following list of medical conditions have 'Diarrhea' or similar listed as a medical complication in our database.


By using this site you agree to our Terms of Use. Information provided on this site is for informational purposes only; it is not intended as a substitute for advice from your own medical team. The information on this site is not to be used for diagnosing or treating any health concerns you may have - please contact your physician or health care professional for all your medical needs. Please see our Terms of Use.

Home | Symptoms | Diseases | Diagnosis | Videos | Tools | Forum | About Us | Terms of Use | Privacy Policy | Site Map | Advertise