Diagnosis is guided by the person's presenting symptoms and laboratory findings. The gold standard imaging modality for the presence of gallstones is ultrasound of the right upper quadrant. There are many reasons for this choice, including no exposure to radiation, low cost, and availability in city, urban, and rural hospitals. Gallstones are detected with a specificity and sensitivity of greater than 95% with ultrasound. Further signs on ultrasound may suggest cholecystitis or choledocholithiasis. Computed Topography (CT) is not indicated when investigating for gallbladder disease as 60% of stones are "not" radiopaque. CT should only be utilized if other intraabdominal pathology exists or the diagnosis is uncertain. Endoscopic retrograde cholangiopancreatography (ERCP) should be used only if lab tests suggest the existence of a gallstone in the bile duct. ERCP is then both diagnostic and therapeutic.

It is unclear whether those experiencing a gallstone attack should receive surgical treatment or not. The scientific basis to assess whether surgery outperformed other treatment was insufficient and better studies were needed as of a SBU report in 2017. Treatment of biliary colic is dictated by the underlying cause. The presence of gallstones, usually visualized by ultrasound, generally necessitates a surgical treatment (removal of the gall bladder, typically via laparoscopy). Removal of the gallbladder with surgery, known as a cholecystectomy, is the definitive surgical treatment for biliary colic. A 2013 Cochrane review found tentative evidence to suggest that early gallbladder removal may be better than delayed removal. Early laparoscopic cholescystectomy happens within 72 hours of diagnosis. In a Cochrane review that evaluated receiving early versus delayed surgery, they found that 23% of those who waited on average 4 months ended up in hospital for complications, compared to none with early intervention with surgery. Early intervention has other advantages including reduced number of visits to the emergency department, less conversions to an open surgery, less operating time required, reduced time in hospital post operatively. The Swedish agency SBU estimated in 2017 that increasing acute phase surgeries could

free multiple in-hospital days per patient and would additionally spare pain and suffering in wait of receiving an operation. The report found that those with acute inflammation of the gallbladder can be surgically treated in the acute phase, within a few days of symptom debut, without increasing the risk for complications (compared to when the surgery is done later in an asymptomatic stage).

Cholestasis can be suspected when there is an elevation of both 5'-nucleotidase and ALP enzymes. With a few exceptions, the optimal test for cholestasis would be elevations of serum bile acid levels. However, this is not normally available in most clinical settings. The gamma-glutamyl transferase (GGT) enzyme was previously thought to be helpful in confirming a hepatic source of ALP; however, GGT elevations lack the necessary specificity to be a useful confirmatory test for ALP. Normally GGT and ALP are anchored to membranes of hepatocytes and are released in small amounts in hepatocellular damage. In cholestasis, synthesis of these enzymes is induced and they are made soluble. GGT is elevated because it leaks out from the bile duct cells due to pressure from inside bile ducts.

In a later stage of cholestasis AST, ALT and bilirubin may be elevated due to liver damage as a secondary effect of cholestasis.

Extrahepatic cholestasis can usually be treated by surgery.

Pruritis in cholestatic jaundice is treated by Antihistamines, Ursodeoxycholic Acid, Phenobarbital

For diagnosis, measures of liver biochemistry and pancreatic enzymes are performed. Along with ruling out structural abnormalities, normally by performing an abdominal ultrasound and endoscopic retrograde cholangiopancreatography (ERCP). Measurements of bile transit when performing ERCP are taken to help evaluate different treatment options.

Sphincter of Oddi dysfunction is best diagnosed using manometry-an internal test done to measure the pressures within surrounding ducts to determine whether or not the muscle is functioning normally.

Early diagnosis is not generally possible. People at high risk, such as women or Native Americans with gallstones, are evaluated closely. Transabdominal ultrasound, CT scan, endoscopic ultrasound, MRI, and MR cholangio-pancreatography (MRCP) can be used for diagnosis. A biopsy is the only certain way to tell whether the tumorous growth is malignant or not.

Xanthogranulomatous cholecystitis (XGC) is a rare form of gallbladder disease which mimics gallbladder cancer although it is not cancerous. It was first discovered and reported in the medical literature in 1976 by J.J. McCoy, Jr., and colleagues.

Individuals are classified as having a functional gallbladder disorder if the above criteria are met, if the gallbladder is present, and if the testing of liver enzymes, conjugated bilirubin, and pancreatic enzymes (amylase and lipase) are normal.

Various modalities of diagnosis are available:

- Cystoscopy

- Colonoscopy

- Poppy seed test

- Transabdominal ultrasonography

- Abdominopelvic CT

- MRI

- Barium enema

- Bourne test

- Cystogram

A definite algorithm of tests is followed for making the diagnosis.

Resection is sometimes a part of a treatment plan, but duodenal cancer is difficult to remove surgically because of the area that it resides in—there are many blood vessels supplying the lower body. Chemotherapy is sometimes used to try to shrink the cancerous mass. Other times intestinal bypass surgery is tried to reroute the stomach to intestine connection around the blockage.

A 'Whipple' procedure is a type of surgery that is sometimes possible with this cancer. In this procedure, the duodenum, a portion of the Pancreas (the head), and the gall bladder are usually removed, the small intestine is brought up to the Pylorus (the valve at the bottom of the stomach) and the Liver and Pancreas digestive enzymes and bile are connected to the small intestine below the Pylorus.

The removal of part of the Pancreas often requires taking Pancreatic Enzyme supplements to aid digestion. These are available in the form of capsules by prescription.

It is not unusual for a patient having received a Whipple procedure to feel perfectly well, and to lead his/her normal life without difficulty.

It is important for the procedure to be performed by a surgeon with extensive experience having done and observed the procedure, as specific competence makes a big difference.

Some patients need to be fitted with tubes to either add nutrients (feeding tubes) or drainage tubes to remove excess processed food that can not pass the blockage.

Diagnostic workup varies by the stone type, but in general:

- Clinical history and physical examination

- Imaging studies

- Some stone types (mainly those with substantial calcium content) can be detected on X-ray and CT scan

- Many stone types can be detected by ultrasound

- Factors contributing to stone formation (as in #Etiology) are often tested:

- Laboratory testing can give levels of relevant substances in blood or urine

- Some stones can be directly recovered (at surgery, or when they leave the body spontaneously) and sent to a laboratory for analysis of content

In humans, enteroliths are rare and may be difficult to distinguish from gall stones. Their chemical composition is diverse, and rarely can a nidus be found. A differential diagnosis of an enterolith requires the enterolith, a normal gallbladder, and a diverticulum.

An enterolith typically forms within a diverticulum. An enterolith formed in a Meckel's diverticulum sometimes is known as a Meckel's enterolith. Improper use of magnesium oxide as a "long-term" laxative has been reported to cause enteroliths and/or medication bezoars.

Most enteroliths are not apparent and cause no complications. However, any complications that do occur are likely to be severe. Of these, bowel obstruction is most common, followed by ileus and perforation. Bowel obstruction and ileus typically occur when a large enterolith is expelled from a diverticulum into the lumen. Perforation typically occurs within the diverticulum.

Most human enteroliths are radiolucent on plain X-rays. They sometimes can be visualized on CT scans without contrast; presence of contrast in the lumen may reveal the enterolith as a void. Most often, they are visualized using ultrasound.

Although recent surveys of enterolith composition are lacking, one early review notes struvite (as in equines), calcium phosphate, and calcium carbonate and reports choleic acid. Deoxycholic acid and cholic acid have also been reported.

In simple cases of obstruction, where there are no complications, a variety of non-surgical and surgical techniques are used to remove the enterolith. These include crushing the enterolith and milking it back to the stomach or forward to the colon, surgical removal via an uninvolved segment of the gastrointestinal tract, and resection of the involved segment.

The cancerous mass tends to block food from getting to the small intestine. If food cannot get to the intestines, it will cause pain, acid reflux, and weight loss because the food cannot get to where it is supposed to be processed and absorbed by the body.

Patients with duodenal cancer may experience abdominal pain, weight loss, nausea, vomiting, and chronic GI bleeding.

Since Rokitansky–Aschoff sinuses can be normally present in the gall badder without any pathology, the radiological detection of these is only of academic interest. Magnetic resonance imaging plays an important role in the diagnosis of Rokitansky–Aschoff sinuses.

Black pigment gallstones can form in Rokitansky–Aschoff sinuses of the gallbladder after the fourth to fifth decades of life in absence of the typical risk factors for bilirubin suprasaturation of bile. Hence, they are associated with gallstones (cholelithiasis). Cases of gall bladder cancer have also been reported to arise from Rokitansky–Aschoff sinuses.

Urethral diverticulum is often an incidental finding. It can be diagnosed using magnetic resonance imaging and/or micturating cystourethrography. Other studies that can be used to diagnose urethral diverticulum include intravenous urography, urethroscopy, and/or ultrasound. Conditions that should be distinguished from urethral diverticulum in a differential diagnosis include overactive bladder, Gartner's duct cyst, Gartner's duct abscess, ectopic caeco-ureterocele, interstitial cystitis, pelvic inflammatory disease, endometriosis, and cancer.

Biliary injury (bile duct injury) is the traumatic damage of the bile ducts. It is most commonly an iatrogenic complication of cholecystectomy — surgical removal of gall bladder, but can also be caused by other operations or by major trauma. The risk of biliary injury is more during laparoscopic cholecystectomy than during open cholecystectomy. Biliary injury may lead to several complications and may even cause death if not diagnosed in time and managed properly. Ideally biliary injury should be managed at a center with facilities and expertise in endoscopy, radiology and surgery.

Modification of predisposing factors can sometimes slow or reverse stone formation. Treatment varies by stone type, but, in general:

- Medication

- Surgery (lithotomy)

- Antibiotics and/or surgery for infections

- Medication

- Extracorporeal shock wave lithotripsy (ESWL) for removal of calculi

The diagnosis of bladder stone includes urinalysis, ultrasonography, x rays or cystoscopy (inserting a small thin camera into the urethra and viewing the bladder). The intravenous pyelogram can also be used to assess the presence of kidney stones. This test involves injecting a radiocontrast agent which is passed into the urinary system. X-ray images are then obtained every few minutes to determine if there is any obstruction to the contrast as it is excreted into the bladder. Today, intravenous pyelogram has been replaced at many health centers by CT scans. CT scans are more sensitive and can identify very small stones not seen by other tests.

If fecal matter passes through the fistula into the bladder, the existence of the fistula may be revealed by pneumaturia or fecaluria.

Colorectal cancer is a disease of old age: It typically originates in the secretory cells lining the gut, and risk factors include diets low in vegetable fibre and high in fat. If a younger person gets such a cancer, it is often associated with hereditary syndromes like Peutz-Jegher's, hereditary nonpolyposis colorectal cancer or familial adenomatous polyposis. Colorectal cancer can be detected through the bleeding of a polyp, colicky bowel pain, a bowel obstruction or the biopsy of a polyp at a screening colonoscopy. A constant feeling of having to go to the toilet or anemia might also point to this kind of cancer.

Use of a colonoscope can find these cancers, and a biopsy can reveal the extent of the involvement of the bowel wall. Removal of a section of the colon is necessary for treatment, with or without chemotherapy. Colorectal cancer has a comparatively good prognosis when detected early.

People get liver cancer (also called "hepatocellular carcinoma, HCC" or "hepatoma)" typically from a prolonged Hepatitis B or C infection or as a result of cirrhosis from chronic alcoholism. Liver cancer may bring about yellowing of the skin and eyes (jaundice), itching (pruritus), or cause a buildup of fluid in the abdomen (ascites). A person may feel an enlarging mass, or the cancer might be revealed by abnormal liver function tests.

An attending practitioner might order a biopsy, an MRI or a CT scan, and a patient might be monitored through blood tests (including alpha-fetoprotein, liver-function tests or ultrasound. These cancers are typically treated according to their TNM stage and whether or not cirrhosis is present. Options include surgical resection, embolisation, ablation or a liver transplant.

Diagnosis is made by patient history of passing air or a sputtering urine stream. CT scans may show air in the urinary bladder or bladder walls.

The primary treatment for urethral diverticulum is surgical. The surgery is conducted transvaginally, usually when there is no acute inflammation to better aid dissection of the delicate tissues.