Fluid retention is a clinical manifestation of patients with multiple organ failure and acute myocardial infarction, among others. Heart failure is defined as heart failure due to primary myocardial myogenic fiber contractile dysfunction, when pump dysfunction is primary. Heart failure occurs when the myocardium contracts weakly for various reasons and there is the ability to eject sufficient blood to the peripheral vessels to meet the metabolic needs of the systemic tissues. What are the tests for fluid retention? X-ray: X-ray is a medical test that involves the use of echocardiography, CT, nuclear imaging, MRI, and other tests. X-ray examination is divided into two types: general examination and imaging examination. Among the former, fluoroscopy and photography are the most basic methods, which are simple and easy to perform and should be used first. Cardiovascular angiography is the rapid injection of contrast into the heart and large blood vessels to show the morphology and hemodynamic changes of the heart and large blood vessels, providing valuable information for the diagnosis of heart and large blood vessel diseases and for surgical treatment. Blood electrolyte test: It is to test the content of various electrolytes in human blood, such as kidney disease, diabetes and endocrine diseases. The test is usually performed by venous blood collection. Glomerular function test: It is an auxiliary test to check whether the glomerular function is normal. The basic functions of the kidney are to excrete metabolic waste, regulate and maintain the balance of water, electrolytes, acid-base and osmotic pressure, and secrete endocrine hormones. Urine excretion is one of the main physiological functions of the kidney, with 180 liters of primary urine formed from glomerular filtration daily. Among the tests are serum urea nitrogen (BUN) measurement, blood creatinine (Cr) measurement, and endogenous creatinine clearance (Ccr) measurement. Serum globulin: It is a mixture of various proteins, including immunoglobulin veneer and complement with high content of defense function, various glycoproteins, metal binding proteins, various lipoproteins, enzymes, etc. The amount of globulin is generally obtained by subtracting albumin from total protein.