Tumor markers + ultrasound + MRI The determination of tumor markers provides a lot of help for the diagnosis of gallbladder cancer. For example, serum carcinoembryonic antigen (CEA) >4ng/ml has 93% specificity and 50% sensitivity in diagnosing gallbladder cancer with clinical manifestations; CA199 serum level >20U/ml has 79.2% sensitivity and 89.2% specificity. However, it may not be elevated in early cancerous cases, or when combined with other gastrointestinal diseases and certain tumors, false positive results may occur with this test, so it must be combined with imaging tests. Ultrasound is the simplest and most reliable way to show the gallbladder. Ultrasound has an accuracy rate of more than 90% and is the first choice for diagnosing gallbladder diseases. With the continuous replacement of instruments, it is now possible to clearly observe not only the size of the gallbladder lesion, but also the blood flow of the lesion to determine whether cancer has occurred, and to observe whether there are obvious lymph node metastases and whether the liver is involved, and experienced examiners can even determine which layer of the gallbladder is involved in the lesion. MRI has become an ideal tool for detecting gallbladder cancer because of its good tissue contrast and multifaceted imaging features, which can detect thickening of the gallbladder wall, infiltration of the liver parenchyma, and metastatic enlargement of the surrounding lymph nodes.