The diagnosis of<unk>  is suggested by the history (abdominal pain, nausea, vomiting, fever) and physical examinations in addition to laboratory and ultrasonographic testing. Boas's sign, which is pain in the area below the right scapula, can be a symptom of acute<unk> . Blood tests In someone suspected of having<unk> , blood tests are performed for markers of inflammation (e.g. complete blood count, C-reactive protein), as well as bilirubin levels in order to assess for bile duct blockage. Complete blood count typically shows an increased white blood count (12,000–15,000/mcL). C-reactive protein is usually elevated although not commonly measured in the United States. Bilirubin levels are often mildly elevated (1–4 mg/dL). If bilirubin levels are more significantly elevated, alternate or additional diagnoses should be considered such as gallstone blocking the common bile duct (common bile duct stone). Less commonly, blood aminotransferases are elevated. The degree of elevation of these laboratory values may depend on the degree of inflammation of the gallbladder. Imaging Right upper quadrant abdominal ultrasound is most commonly used to diagnose<unk> . Ultrasound findings suggestive of acute<unk>  include gallstones, pericholecystic fluid (fluid surrounding the gallbladder), gallbladder wall thickening (wall thickness over 3 mm), dilation of the bile duct, and sonographic Murphy's sign. Given its higher sensitivity, hepatic iminodiacetic acid (HIDA) scan can be used if ultrasound is not diagnostic. CT scan may also be used if complications such as perforation or gangrene are suspected. File:Ultrasonography of<unk> .Abdominal ultrasonography showing gallstones, wall thickening and fluid around the gall bladder File:Ultrasonography of sludge and gallstones, annotated.Gallstones and biliary sludge, but the gallbladder wall is not clearly thickened, with no edema in the pericholecystic fat, thus not<unk> . File:Pacutecholecystitits.Acute<unk>  as seen on ultrasound. The closed arrow points to gallbladder wall thickening. Open arrow points to stones in the GB File:GBthick,GS,largeMark.Acute<unk>  with gallbladder wall thickening, a large gallstone, and a large gallbladder File:UOTW 30 - Ultrasound of the Week 1.Significant gallbladder wall thickening File:UOTW 30 - Ultrasound of the Week 2.Significant gallbladder wall thickening Histopathology Histopathology is indicated if preoperative imaging and/or gross examination gives a suspicion of gallbladder cancer. File:Gross pathology of gallbladder carcinoma.Gross examination of gallbladder carcinoma, with a prominent nodule. File:Histopathology of gallbladder carcinoma.Histopathology of gallbladder carcinoma, with marked nuclear pleomorphism. File:Histopathology of eosinophilic<unk> .Histopathology of eosinophilic<unk>  File:Gross pathology of cholesterolosis.Gross examination of gallbladder cholesterolosis, with yellow streaks of cholesterol deposition. File:Histopatholgoy of acute gangrenous<unk> .Histopathology of acute gangrenous<unk> , showing necrosis, neutrophils and partially sloughed off mucosa. Differential diagnosis Many other diagnoses can have similar symptoms as<unk> . Additionally the symptoms of chronic<unk>  are commonly vague and can be mistaken for other diseases. These alternative diagnoses include but are not limited to: * Perforated peptic ulcer * Acute pancreatitis * Liver abscess * Pneumonia * Myocardial ischemia * Hiatal hernia * Biliary colic * Choledocholithiasis * Cholangitis * Appendicitis * Colitis * Acute peptic ulcer exacerbation * Amoebic liver abscess * Acute intestinal obstruction * Kidney stone * Biliary ascariasis
Cholecystitis
Hepatitis
Cholangitis 
Angina
Biliary colic
Peptic ulcer disease
Pancreatitis
Pneumonia