A Breath Test is a noninvasive diagnostic test that measures specific gases in exhaled air. In gastroenterology, it is commonly used to assess infection, digestion, and absorption. It can help clinicians evaluate symptoms such as bloating, diarrhea, abdominal discomfort, and nausea. Results are interpreted in clinical context rather than as a stand-alone diagnosis.

Small intestinal bacterial overgrowth (SIBO) is a condition in which excessive bacteria are present in the small intestine. It is discussed most often in gastroenterology when evaluating bloating, diarrhea, abdominal discomfort, or malabsorption. SIBO is not a single disease and typically reflects an underlying problem with gut motility, anatomy, or host defenses. Clinicians use the term in both outpatient and inpatient settings, including general gastroenterology and GI surgery follow-up.

Small Intestinal Bacterial Overgrowth is a condition where too many microbes are present in the small intestine. It can disrupt digestion and absorption and contribute to symptoms like bloating and diarrhea. In clinical care, it is discussed in gastroenterology clinics, nutrition settings, and sometimes surgical follow-up. It is commonly evaluated using breath testing or small-bowel fluid sampling in selected cases.

A HIDA Scan is a nuclear medicine imaging test that tracks how bile is made and moves through the liver and biliary system. It uses a small amount of radioactive tracer injected into a vein and a special camera to create images over time. It is commonly used in emergency and outpatient settings to evaluate gallbladder and bile duct function. It can help clarify causes of right upper abdominal pain, jaundice, or suspected bile leaks after surgery.

A Gastric Emptying Study is a diagnostic test that measures how quickly a meal leaves the stomach. It is most commonly performed in nuclear medicine using a small amount of radiotracer mixed into food. Clinicians use it to evaluate symptoms that suggest abnormal stomach motility (movement). It is frequently ordered in gastroenterology and GI surgery settings.

Alpha Fetoprotein is a protein normally made in large amounts by a developing fetus. In healthy non-pregnant adults, Alpha Fetoprotein is usually present at very low levels. Clinicians most often measure Alpha Fetoprotein with a blood test. It is commonly discussed in hepatology for liver tumors and in obstetrics for fetal assessment.

CA 19-9 is a blood-based biomarker commonly discussed in pancreatic and biliary (hepatobiliary) disease. It is short for carbohydrate antigen 19-9 (CA 19-9), a sugar-containing marker found on certain mucin proteins. Clinicians most often use CA 19-9 to support cancer evaluation and to follow disease over time. It is not a stand-alone diagnostic test and is interpreted in clinical context.

CEA stands for carcinoembryonic antigen. CEA is a blood-measurable protein that can be higher in some cancers, especially colorectal adenocarcinoma. CEA is most commonly used as a **tumor marker** to support monitoring over time. CEA is also referenced in gastroenterology, hepatology, and GI oncology when interpreting cancer follow-up and liver-related clearance.

Tumor Markers are measurable substances linked to cancer or to the body’s response to cancer. They are most often checked in blood, but some are measured in urine, stool, or tissue. In gastroenterology and hepatology, they are commonly used alongside imaging and endoscopy. They help clinicians assess risk, track disease over time, and monitor treatment response.

Lipase is an enzyme that breaks down dietary fat into smaller molecules the body can absorb. In clinical care, Lipase most often refers to a blood test measuring pancreatic lipase activity. It is commonly used when clinicians evaluate abdominal pain and suspected pancreatic disease. It is also discussed in digestion, malabsorption, and pancreatic function.