How To Test for IBS

Medically Reviewed by: Nicole Anne Vergara, RD

About 5 to 15% of the worldwide population has IBS, which affects women twice as frequently as it does males. Usually, symptoms don't appear until a person is in their 20s or 30s and most people don't visit their doctors to diagnose and confirm if they have IBS.

Almost 2,000 patients with IBS confirmed that they never get tested and diagnosed with IBS during the onset of the symptoms. According to a survey, it took patients 6.6 years before going to a healthcare provider to confirm their IBS.

In this article, we will be talking about how IBS is diagnosed. Additionally, you will also learn the possible medical procedures that you have to expect when you visit your GI doctor.

ibs symptoms


IBS Symptoms

IBS symptoms can vary from one person to another. Ruling out your symptoms can help your doctors identify what interventions and symptom management would work best for you.

It is important to know the most common symptoms that may happen to you and how to manage them effectively.

Common Symptoms of IBS:

  • Cramping

  • Sharp abdominal pain

  • Bloating

  • Distention

  • Fullness

  • Flatulence

  • Changes in bowel movements

Other Symptoms:

  • Lethargy (lack of energy)

  • Heartburn

  • Always feeling sick

  • Muscle pains

  • Dizziness

  • Painful menstruation

[Related: How Long Does IBS Last? (Guide to Symptoms, Duration, Treatment)]

IBS Causes

The causes of IBS remain unknown but studies are still ongoing to learn more about the exact reasons behind the development of IBS in people.

On a positive note, experts have confirmed some of the probable causes of IBS. This may be a combination of different factors and digestive issues such as:

Stress during the early stages of life

stress and IBS

Stressful childhood experiences cause the protein known as a nerve growth factor to communicate abnormally, starting a chain of events that eventually results in the development of irritable bowel syndrome (IBS).

IBS was most strongly predicted by emotional abuse. After adjusting for the existence of psychological and other non-gastrointestinal symptoms, the correlation between early trauma and IBS was also less strong.

Small Intestinal Bacterial Overgrowth (SIBO)

The increase in the number of bacteria in your small intestine can irritate your digestive system.

Studies provide evidence that SIBO might be an underlying factor in IBS. The first is that several studies have discovered that IBS patients are substantially more likely than unaffected individuals to have a positive Hydrogen Breath Test (HBT), suggesting that SIBO may be a problem.

Additionally, the study's discovery confirmed that many people see a considerable reduction in IBS symptoms after trying particular antibiotics.

These antibiotics are accessible to combat any bacteria that might be hiding in the small intestine because they are not absorbed in the stomach.

Mental health issues

IBS sufferers may be more sensitive to emotional issues, even though psychological issues like worry may not cause digestive illness.

Stress, anxiety, and depression can set off chemicals in the brain that activate pain signals in the gut, which could cause your colon to react.


family inherited IBS

Genetics have been linked to the onset of IBS, according to research. You are also more prone to get the symptoms as an adult if your family has a history of IBS.

If some of your family members have been diagnosed with irritable bowel syndrome, and you have been noticing some of its signs, reach out to your doctor as soon as possible.

Food intolerance

Some people who have sensitive colons are prone to certain food intolerances, which can also be a cause of IBS.

According to a study, 20–65% of IBS patients are attributing their symptoms to food hypersensitivity.

It appears that the prevalence of food hypersensitivity in the IBS population is higher than in the general population. In fact, many IBS sufferers claim that certain meals make their symptoms worse.

Intestinal Muscle Contractions

Intestinal Muscle Contractions

Layers of muscle that contract as they carry food through your digestive tract line the inside of your intestines.

Gas, bloating, and diarrhea might result in stronger and longer than typical contractions. Weak contractions might hinder the passage of food and result in dry, firm stools.

Severe infection

After a severe case of diarrhea brought on by germs or a virus, IBS may appear. It is known as gastroenteritis.

There may be a connection between IBS and an overabundance of bacteria in the intestines (bacterial overgrowth).

Changes in the gut microbiome

According to research, those with IBS may have different microorganisms than those without the condition.


IBS Diagnosis and Testing

How is IBS diagnosed?

IBS can be accurately diagnosed with a thorough grasp of the symptoms, a thorough medical history, a physical exam, and the lack of any alarming symptoms. To eliminate other illnesses as probable sources of symptoms, minimal testing may be necessary.

A group of medical professionals developed the initial criteria for assessing irritable bowel syndrome in the 1990s (IBS).

The "gold standard" for the diagnosis of IBS in clinical research studies is the set of criteria known as the Rome Criteria.

According to the Rome IV diagnostic criteria for IBS, some symptoms must have started at least six months prior to and been present for the preceding three (3) months in order to qualify as IBS.

Also, the Rome IV criteria qualify IBS patients if they have two or more of the following symptoms related to abdominal pain:

  • Abdominal pain is related to defecation

  • Abdominal pain is associated with changes in the frequency of bowel movement

  • Abdominal pain is associated with changes in the appearance of stool

To clarify these symptoms further, the following reviews and examinations would also be conducted by your GI physician:

Review of Symptoms

To diagnose IBS, your doctor will interview you about your symptoms and search for a specific pattern in them. This will include the above-mentioned criteria to further verify if you have IBS.

Additionally, your physician will ask you about the duration of your symptoms. You will more likely to be diagnosed with irritable bowel syndrome if:

  • Symptoms occur at least once a week for the past 3 months; and

  • Onset of symptoms started at least 6 months ago

However, your physician may diagnose IBS even if you've had the symptoms for shorter periods of time. This can be further assessed by medical procedures.

Other symptoms may also be asked to check for other conditions like inflammatory bowel disease or other health conditions. The symptoms that could be a sign of other medical conditions are the following:

  • Rectal bleeding

  • Severe weight loss

  • Anemia

  • Bloody stool


Medical Procedures Done to Check for IBS:

How To Test for IBS

Diagnosing Irritable Bowel Syndrome (IBS) requires various tests to rule out other conditions. This medical condition mimics other diseases and gut conditions.

Thus, your healthcare provider would recommend you take one or more of these tests:

Stool Tests

A stool test is performed to check your stools for any presence of internal parasites, blood, or bacterial infections.

The test can also be used to detect other conditions like inflammatory bowel disease and malabsorption syndromes.

Blood Tests

Your healthcare professional will conduct a complete blood screening in a laboratory. This screening is usually done to check for other medical conditions that you might have, such as digestive diseases, inflammatory bowel disease, anemia, tissue damage, or celiac disease.

Two blood tests are available to help in the diagnosis of IBS which are IBSchek and IBS-Smart

Both blood tests are intended to help diagnose adults with irritable bowel syndrome with diarrhea as the predominant symptom (IBS-D) or irritable bowel syndrome with mixed bowel habits (IBS-M).

Doctors would also check for specific antibodies known to be connected to IBS that were produced after a GI infection (post-infectious IBS).

In comparison to healthy individuals, patients with IBS-D or IBS-M had higher positive rates for these antibodies.

On the contrary, the amount of antibodies present in your body is not always a basis for being diagnosed with IBS. Having a negative test for these antibodies does not also conclude that you do not have IBS.

Further testing and medical procedures will be done to get an accurate diagnosis.


A colonoscopy is a medical procedure in which a doctor uses a long, flexible tube with a light and camera attached to it to examine the inside of the large intestine (colon) and rectum. This procedure can also be used to look for signs of colon cancer or other irregularities in your GI tract.

Upper endoscopy

Upper endoscopy

The esophagus, the tube that connects your mouth and stomach, is entered through your throat with a long, flexible tube. Your healthcare professional can see your upper digestive tract thanks to a camera on the end of the tube. A tissue sample (biopsy) may be taken during an endoscopy. It is possible to take a sample of the fluid to check for bacterial overgrowth. If celiac disease is suspected, an endoscopy may be suggested.

Breath Test

A hydrogen breath test is also one of the most common tests to check for Irritable Bowel Syndrome.

The hydrogen breath test is a quick medical procedure that checks the amount of hydrogen gas (H02) in your breath when you exhale. It is employed to aid in the diagnosis of common digestive issues like SIBO, IBS, and lactose intolerance. The test's various iterations gauge how you digest various sugars.

ibs and stress

Psychological Tests

Stress, anxiety, depression, and other mental health conditions are major triggers of IBS flare-ups. A psychological assessment may be ordered by your GI physician to effectively manage your emotional stressors and IBS symptoms.

Anorectal Manometry

Anorectal manometry is a test that measures muscle tone and sensation in the rectum and anus. It is used to diagnose problems with the anal sphincter muscles or nerves.

Lactose Intolerance Test

Lactose Intolerance Test

Individuals with lactose intolerance do not produce enough lactase. Lactase is an enzyme used to digest the sugar from dairy products.

This intolerance can lead to abdominal pain, excessive gas, and diarrhea which are the same symptoms of Irritable Bowel Syndrome (IBS).

[Try these: 5 Nutritious Vegan Low-FODMAP Breakfast Meals To Kickstart Your Day (Using Lactose-Free Milk!)

The Next Step After Being Diagnosed With Irritable bowel Syndrome (IBS)

After being diagnosed with irritable bowel syndrome, your next goal should be to give your body what it needs - healing and a major transformation in your lifestyle.

For more information, read our comprehensive guide to IBS over-the-counter medications and home remedies.

Sign up for our integrated care plan to have a comprehensive IBS care plan that includes medical, nutritional, and overall health therapies.


Medically Reviewed by:

Onikepe Adegbola MD PhD is a board-certified physician who founded, a digital gut health platform for gastrointestinal conditions such as IBS, IBD, SIBO and celiac disease.

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