The liver is a reddish-brown organ that is in the upper right portion of the abdominal cavity. The liver's functions include the production of bile, which removes waste and aids in the digestion of fat in the small intestine; regulation of blood clotting; clearing of drugs and toxins from the blood; and converting excess glucose to glycogen for storage, says the University of Maryland Medical Center (UMMC). There are a series of blood tests that doctors use to determine whether or not the liver is working properly.
Serum Albumin Test
Albumin is a protein that the liver produces, and it helps to transport small molecules such as drugs through the blood. The serum albumin test determines the concentration of this protein in the blood serum, says the U.S. National Library of Medicine (USNLM). A health care provider draws a blood sample into a test tube, and then centrifuges the sample to drive the blood cells to the bottom of the tube. The provider then assays the clear top portion of blood (serum) to determine how much albumin is present. According to the USNLM, a normal albumin concentration is 3.4 to 5.4 grams per deciliter of serum. An albumin concentration that is lower than normal may be a sign of a liver disease like hepatitis or cirrhosis that is compromising the ability of the liver to produce albumin.
Alanine Transaminase (ALT) Test
According to the University of Illinois Medical Center at Chicago (UIMC), the alanine transaminase test determines the level of the enzyme alanine transaminase in the blood. Normal blood levels of this enzyme range from 6 to 59 units per liter. An injured or diseased liver releases this enzyme into the bloodstream so blood levels will rise above the normal range. High blood ALT levels can result from conditions such as alcoholic liver disease, liver cancer, congested bile ducts, cirrhosis or hepatitis, says the UIMC.
5΄-Nucleotidase Test
The U.S. National Library of Medicine says that 5΄-nucleotidase (5΄-NT) is a protein that the liver produces, and a blood test can measure the amount of this protein in the bloodstream. If a patient shows signs of a liver problem, a doctor may order this test as a check on liver function. Under normal conditions, this protein is present at a concentration of 2 to 17 units per liter of blood. Elevated blood levels of 5΄-NT may be a sign of cholestasis, which means that there is a bile duct obstruction that is blocking the flow of bile from the liver, says the U.S. National Library of Medicine. Other conditions that raise 5΄-NT levels are hepatitis and liver tumors.
