SerumAlbuminGradient

Serum Albumin Gradient (SAG) is a diagnostic tool used in the evaluation of liver disease, particularly in the context of cirrhosis. It involves measuring the albumin concentration in the blood serum at different levels, typically at the top, middle, and bottom of the serum column after centrifugation. The principle behind SAG is that in patients with cirrhosis, the albumin concentration decreases from the top to the bottom of the serum column due to the presence of ascites, a condition characterized by the accumulation of fluid in the abdominal cavity. This gradient is absent or minimal in patients without cirrhosis.

The SAG test is performed by drawing a blood sample and allowing it to clot. The serum is then carefully removed and divided into three equal parts. Each part is centrifuged to separate the albumin from other proteins. The albumin concentration is measured in each layer, and the difference between the top and bottom layers is calculated. A significant gradient (typically >1.5 g/L) is indicative of cirrhosis.

SAG is considered a sensitive and specific test for the diagnosis of cirrhosis. It is particularly useful in patients with ascites, where other diagnostic tests may be less reliable. However, it is not without limitations. The test requires careful technique to avoid contamination and ensure accurate results. Additionally, the presence of other conditions that cause a serum albumin gradient, such as nephrotic syndrome, can lead to false-positive results.

In summary, Serum Albumin Gradient is a valuable diagnostic tool in the evaluation of liver disease, particularly in the context of cirrhosis. It provides a simple, non-invasive method to assess the presence of ascites and can aid in the diagnosis and management of liver disease. However, it should be interpreted in the context of the patient's clinical presentation and other diagnostic tests.