Ulta Lab Tests

Digestive System Tests

Digestive testing helps explain abdominal pain, bloating, diarrhea/constipation, heartburn, blood in stool, weight loss, and post-travel diarrhea. Core tools include H. pylori testing (urea breath or stool antigen), fecal calprotectin/lactoferrin (IBD vs IBS triage), celiac serology, stool pathogen PCR (± C. difficile), fecal elastase-1(pancreas), serum lipase (pancreatitis), occult blood/FIT, and nutrient panels (iron, B12, folate, Vitamin D). Results guide whether you need treatment, endoscopy, or specialist follow-up—always with clinician review.

What It Tests

“Digestive system tests” include blood, stool, breath, and urine tests that can help you and your clinician:

  • Differentiate inflammation (IBD) from functional disorders (IBS) using fecal calprotectin/lactoferrin and CRP/ESR.

  • Detect infection (stool PCR/culture, C. difficile toxin/PCR, parasite antigens/O&P).

  • Evaluate ulcer symptoms and confirm H. pylori cure (urea breath test or stool antigen).

  • Check malabsorption and nutrition (iron studies, B12, folate, Vitamin D; fecal fat).

  • Assess pancreatic function (fecal elastase-1) and acute pancreatitis (lipase).

  • Triage occult GI bleeding (FIT/gFOBT) and decide on colonoscopy.

  • Screen for celiac disease (tTG-IgA total IgA; EMA; DGP-IgG if IgA deficient).

Key Tests

Test Also Called (Synonyms) What It Measures Typical Prep (fasting?) Specimen Related Panels
H. pylori Urea Breath Test UBT Active H. pylori infection; test-of-cure Usually fast 1–6h; hold PPIs ~2 wks; antibiotics/bismuth ~4 wks (per clinician/lab) Breath H. pylori / Dyspepsia
H. pylori Stool Antigen HpSA Active H. pylori infection; test-of-cure No special diet; med holds similar to UBT Stool H. pylori / Dyspepsia
Fecal Calprotectin FCP Neutrophil protein—marker of intestinal inflammation Avoid NSAIDs if possible; follow kit Stool IBD vs IBS Triage
Fecal Lactoferrin — Another stool inflammation marker Follow kit Stool IBD vs IBS Triage
Celiac Panel (first-line) tTG-IgA total IgA Autoantibodies to gluten-related autoimmunity Stay on glutenbefore testing Blood Celiac Evaluation
DGP-IgG Deamidated gliadin peptide IgG Use if IgA deficient or equivocal results Stay on gluten Blood Celiac Evaluation
Stool Pathogen PCR Panel GI PCR Bacterial/viral/parasitic pathogen DNA Follow kit; no toilet-water contamination Stool Infectious Diarrhea
C. difficile Toxin/PCR — C. diff infection detection Watery stool preferred; follow kit Stool Infectious Diarrhea
Ova & Parasite Exam O&P Microscopy for parasites Multiple samples may be needed Stool Infectious Diarrhea
Fecal Elastase-1 FE-1 Exocrine pancreatic insufficiency screen Random stool sample Stool Pancreatic Function
Serum Lipase — Acute pancreatitis (more specific than amylase) No fasting typically Blood Pancreatitis Workup
Amylase — Adjunct enzyme (less specific) No fasting Blood Pancreatitis Workup
FIT Fecal immunochemical test Occult lower GI bleeding(screen/triage) Follow kit exactly Stool Occult GI Bleeding / CRC
CRP / ESR — Systemic inflammation context No fasting Blood IBD vs IBS Triage
Iron Studies Ferritin Iron/TIBC/TSAT ferritin Iron deficiency (common in GI blood loss) Often morning; some prefer fasting Blood Malabsorption/Anemia
Vitamin B12 / Folate Cobalamin / Folacin Nutrient malabsorption No fasting Blood Malabsorption/Nutrition
Vitamin D (25-OH) 25-hydroxyvitamin D Bone and immune context in malabsorption No fasting Blood Nutrition
CMP / Liver Panel ALT/AST/ALP/GGT/bilirubin Liver/biliary context (cholestasis, hepatitis, meds) Often non-fasting Blood Liver & Biliary
Breath Tests HBT: lactulose/glucose; Lactose/Fructose HBT SIBO or carb intolerance Overnight fast; prep diet; med holds Breath SIBO/Carb Intolerance

When to Test

  • Persistent or recurrent symptoms >4 weeks: abdominal pain, bloating, change in bowel habits, unexplained weight loss, fatigue, or iron-deficiency anemia.

  • Alarm signs: blood in stool/black stools, fever, nocturnal symptoms, age >50 with new symptoms, severe dehydration—seek clinician evaluation; consider FIT/occult blood and endoscopy referral.

  • IBD vs IBS triage: start with fecal calprotectin (± lactoferrin) and CRP/ESR; high values support inflammation.

  • Ulcer/dyspepsia or prior H. pylori: noninvasive UBT or HpSA; test-of-cure after treatment and proper med holds.

  • Acute diarrhea or post-travel: stool PCR ± C. difficile testing (antibiotic exposure).

  • Suspected pancreatic disease: lipase for acute pain; fecal elastase-1 for chronic greasy stools/weight loss.

  • Celiac suspicion: chronic diarrhea, bloating, anemia, dermatitis herpetiformis, family history—order tTG-IgA total IgA (stay on gluten).

  • Bloating, gas, carb intolerance, or suspected SIBO (if offered): hydrogen/methane breath tests with strict prep.

How to Prepare

  • Stool tests: Use the supplied collection device. Avoid mixing with urine or toilet water. Cap, label, refrigerate/ship as instructed.

  • H. pylori testing: Ask about PPI hold (~2 weeks) and antibiotic/bismuth hold (~4 weeks); small fast may be required for UBT.

  • Celiac serology: Do not start a gluten-free diet before testing (unless your clinician directs a supervised challenge).

  • Breath tests (SIBO/lactose/fructose): Overnight fast; follow low-fermentable prep diet and avoid antibiotics/probiotics as kit directs; no smoking/exercise during the test.

  • Blood tests: Most do not require fasting; follow panel instructions (some nutrient/metabolic panels prefer morning fasting).

  • Medication disclosure: List PPIs, antibiotics, bismuth, NSAIDs, laxatives, iron, probiotics, and biotin (can interfere with some immunoassays).

Interpreting Results

  • Fecal calprotectin/lactoferrin: Higher values suggest intestinal inflammation (IBD, infection, NSAID effect); low-normal favors IBS/functional disorders.

  • H. pylori (UBT/HpSA): Positive = active infection. For test-of-cure, retest after proper medication holds and completion of therapy.

  • Celiac serology: Positive tTG-IgA with normal total IgA (± EMA) strengthens suspicion. IgA deficiency → check DGP-IgG. Diagnosis often requires GI specialist evaluation (± biopsy).

  • FIT/gFOBT: Positive requires colonoscopy to identify bleeding source; negative does not exclude all lesions—repeat per schedule if used for screening.

  • Stool PCR/culture/O&P: Positive results require correlation with travel/exposure and symptoms; colonization is possible.

  • Fecal elastase-1: Low values support exocrine pancreatic insufficiency—interpret with symptoms and nutrition status.

  • Lipase (± amylase): Markedly elevated in acute pancreatitis with compatible symptoms; imaging and exam confirm severity.

  • Iron/B12/folate/Vitamin D: Identify malabsorption or dietary gaps; link with CBC and clinical picture.

  • Liver panel: Elevations may reflect hepatitis, cholestasis, medication effects, or biliary obstruction—tie to symptoms and imaging.

Related Conditions

  • IBD (Crohn’s disease, Ulcerative colitis)

  • IBS (Irritable Bowel Syndrome)

  • H. pylori infection / Peptic ulcer disease

  • Celiac disease (gluten-related autoimmunity)

  • Acute & Chronic Pancreatitis / Exocrine Pancreatic Insufficiency (EPI)

  • Infectious gastroenteritis / Traveler’s diarrhea / C. difficile

  • GERD & Dyspepsia

  • Occult GI bleeding / Colorectal cancer screening 

  • Liver & Biliary disease

Bundles & Panels

  • Digestive Health – Basic – Includes 4 tests (61 biomarkers) focusing on core digestive health markers including nutrient absorption and gut function. 

  • Digestive Health – Advanced – Contains 11 tests (70 biomarkers) expanding on Basic with additional gut inflammation, enzyme deficiency, and absorption markers. 

  • Gastrointestinal Pathogen Panel – Single test (9 biomarkers) using nucleic acid detection to identify key enteric pathogens that may drive digestive symptoms.

FAQs

Do I need to fast for stool or breath tests?
Stool tests usually don’t require fasting. Breath tests typically need an overnight fast and special prep diet—follow kit instructions.

IBS vs IBD—how can labs help tell the difference?
Fecal calprotectin/lactoferrin and CRP/ESR support inflammation (IBD). Normal values favor IBS, though clinical review is still needed.

How should I prepare for an H. pylori test or test-of-cure?
Ask about holding PPIs (~2 weeks) and antibiotics/bismuth (~4 weeks). Some UBT protocols require a short fast.

Should I stop gluten before a celiac test?
No. Stay on a gluten-containing diet unless your clinician directs a supervised challenge; otherwise tests can be falsely negative.

Can NSAIDs, PPIs, antibiotics, or probiotics change my results?
Yes—NSAIDs can elevate fecal calprotectin; PPIs/antibiotics/bismuth affect H. pylori tests; probiotics/antibiotics influence stool PCR. Disclose everything.

What happens after a positive FIT or occult blood test?
You’ll typically be referred for colonoscopy to find and treat the bleeding source.

What does a low fecal elastase mean?
It supports exocrine pancreatic insufficiency, especially with greasy stools and weight loss—confirm with symptoms and nutrition work-up.

When do I need imaging or endoscopy?
With alarm signs (bleeding, weight loss, fever, nocturnal symptoms), persistent symptoms, or abnormal labs—your clinician will guide timing and prep.

How quickly will I get results and how often should I retest?
Many stool PCRs return in 1–3 days; calprotectin, HpSA, and serologies in 1–3 days. Retesting depends on your plan (e.g., test-of-cure for H. pylori, monitoring in IBD).

References

  • American College of Gastroenterology (ACG) — Dyspepsia/H. pylori, IBD/IBS, celiac, infectious diarrhea guidance

  • American Gastroenterological Association (AGA) / British Society of Gastroenterology (BSG) — Calprotectin use, celiac testing, chronic diarrhea evaluation

  • NIH / NIDDK — Celiac disease, IBD, pancreatitis, and malabsorption resources

  • CDC — Traveler’s diarrhea, C. difficile overview

  • Mayo Clinic — Patient-friendly overviews for H. pylori, calprotectin, FIT, pancreatitis, and celiac testing

  • Peer-reviewed reviews (PubMed) on fecal calprotectin thresholds, H. pylori test-of-cure timing, and fecal elastase interpretation

Last reviewed: September 2025 by Ulta Lab Tests Medcial Review Team

Any issues with your digestive system can lead to much bigger problems later. Learn the importance of digestive system lab tests here.

Order your lab tests here to keep track of your digestive health and utilize the data to make educated health decisions. To understand more about the lab tests available to identify and monitor the impact of digestive issues on your health, click on the link below.

Visit the link below to learn more about GI tract disorders and the lab tests available to screen, diagnose, and monitor your health.

 
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All About Digestive System Conditions & Lab Testing

People tend to overlook their digestive health. With so much focus on cancer, heart attacks, and strokes, it's easy for your gut health to get lost in the shuffle.

That's why it's important to have digestive lab tests done regularly. Catching digestive system conditions before they start is the best form of medicine.

If monitoring your gut health is new to you, don't worry. In this article, we're going to cover everything you need to know about your gut.

Digestive System Conditions

Different GI lab tests monitor the levels of different enzymes and bacteria in your gut. We know what you're thinking, "there are bacteria in my stomach?"

Yes. There are bacteria in your stomach. But, the bacteria in your digestive system are "good" bacteria. It needs to stay at a certain level in your digestive system for your gut to remain healthy.

Several conditions can arise from having an unhealthy digestive system. Let's outline some of them below.

Celiac Disease

Celiac disease is an acute gluten sensitivity in the digestive system. People who live with celiac disease have an immune response that gets triggered in their small intestine every time they eat gluten. Gluten is present in any flour or wheat-based products.

If someone chooses not to treat their Celiac Disease, it can start to affect the absorption of nutrients in their small intestine. The lining of the small intestine will also begin to deteriorate. The damage done to the small intestine could eventually lead to more serious complications.

Signs and Symptoms of Celiac Disease include:

  • Diarrhea
  • Fatigue
  • Bloating
  • Abdominal Pain
  • Weight Loss
  • Constipation
  • Nausea or vomiting

Inflammatory Bowel Disease (IBD)

Inflammatory Bowel Disease is a blanket term that covers several conditions affecting the bowels.  

The two major types of IBD are ulcerative colitis and Crohn's disease. 

Ulcerative colitis involves inflammation and sores (ulcers) along the lining of your large intestine. The condition also affects your colon and rectum.

Crohn's disease is similar in that it also involves the swelling of your digestive tract. Chron's, however, can affect the deeper layers of your digestive tract.

Signs and symptoms of IBD include:

  • Diarrhea
  • Abdominal Pain
  • Fatigue
  • Loss of appetite
  • Unnatural weight loss
  • Blood in the stool

Inflammatory Bowel Syndrome (IBS)

Inflammatory Bowel Syndrome affects both the lower and upper areas of the GI tract. This includes both the small and large intestine and the colon.

Individuals suffering from IBS can experience chronic diarrhea, chronic constipation, or both.  

Doctors believe that in most cases, IBS is brought on by a severe case of food poisoning.

Lactose Intolerance

Lactose intolerance is the inability to digest the sugar lactose fully. The condition arises from a lack of the enzyme lactase in your digestive system.

Lactase is the enzyme responsible for processing lactose. If the lactase levels are too low within your digestive system, it results in lactose intolerance.

Signs and symptoms of lactose intolerance include:

  • Gas
  • Bloating
  • Diarrhea
  • Stomach cramps
  • Nausea or vomiting

Pancreatic Diseases

Problems with your digestive tract can also lead to several pancreatic diseases. Acute pancreatitis is the most common of these conditions.

However, if these conditions don't receive treatment, they can escalate into much bigger problems.

Signs and symptoms of general pancreas malfunction include:

  • Abdominal swelling or pain
  • Nausea or vomiting
  • Excess gas
  • Malnutrition
  • Weight loss
  • Lightly colored stool
  • Foul-smelling stool
  • Fever
  • Diarrhea 

If any of these symptoms persist, it may be a good idea to consult your doctor.

Peptic Ulcer

Peptic ulcers are sores that develop on the inner lining of your stomach. They can also affect the upper section of your small intestine. These can occur as gastric ulcers or duodenal ulcers.

Gastric ulcers occur in the stomach. Duodenal ulcers occur in an upper section of the small intestine, the duodenum.

Signs and symptoms of peptic ulcers include:

  • Feeling full
  • Bloating
  • Belching
  • Burning stomach pain
  • Heartburn
  • Nausea
  • Intolerance to fatty foods

Lab Tests for Digestive Conditions

Digestive lab tests are one of the best strategies to screen, diagnose, and monitor digestive conditions.

Two of the most popular digestive system tests are the fecal occult blood test and stool culture.

The fecal occult blood test will test for hidden blood in the stool. The test involves placing a small amount of stool on a special card. The sample will then be tested in the doctor's office or sent to a lab.

A standard stool culture test searches for abnormal bacteria in the stool. A sample of stool is collected and then sent to the lab by your healthcare provider. Results usually take 2 to 3 days, and then you'll know if abnormal bacteria are present.

In addition to the above lab tests, doctors can also perform imaging tests to get a more in-depth look at your digestive system.

Popular procedures to monitor digestive conditions include:

  • A CT or CAT scan
  • Lower GI series
  • Upper GI series
  • MRI
  • Ultrasound
  • Colonoscopy

Digestive System and Digestive Lab Tests FAQs

Digestive conditions can cover a wide range of conditions and symptoms. It's easy for them to be overlooked if you don't know what you're looking for. Here are some of the most frequently asked questions about digestive conditions.

Q: What Are Common Problems In the Digestive System?

The most common problems in the digestive system include cancer, heartburn, and IBS. Rectal problems such as fissures and hemorrhoids can also occur.

Q: What Are Digestive Problem Symptoms?

Common signs and symptoms of digestive conditions include:

  • Abdominal pain
  • Swelling
  • Bloating
  • Gas
  • Belching
  • Diarrhea
  • Constipation
  • Fatigue

If any of the above symptoms persist for a long period of time, it's a good idea to consult your doctor.

Q: What Tests Are Done For Digestive Conditions? 

An endoscopy, upper GI series, lower GI series, ultrasound, and MRI are common options when screening for digestive conditions.

Q: Does Bloodwork Show Digestive Conditions?

Doctors can order blood tests for digestive issues. If your GI lab tests need to check for levels of a specific substance in the blood, your doctor may order blood work. This is the case with Celiac disease, Crohn's disease, or ulcerative colitis.

Solving Your Digestive System

Ulta Lab Tests offers highly accurate and reliable tests to make informed decisions about your health. Here are a few great things to love about Ulta Lab Tests for your digestive lab tests:

  • You'll get secure and confidential results
  • You don't need health insurance
  • You don't need a physician's referral
  • You'll get affordable pricing
  • We offer a 100% satisfaction guarantee

Order your digestive system health lab tests today, and your results will be provided to you securely and confidentially online in 24 to 48 hours for most tests.

Take control with Ulta Lab Tests today!