| Subject | Contents |
| Definition | A test that measures the amount of 5-N'Tase in the blood. |
| Alternative Names | 5-nucleotidase; 5'-NT |
| How the test is performed | Adult or child: Blood is drawn from a vein ( venipuncture ), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (fill with blood). A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding . Infant or young child: The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding. |
| How to prepare for the test | The health care provider will instruct you, if necessary, to discontinue drugs that may interfere with the test. These include hepatotoxic drugs (e.g., acetaminophen - oral, methyldopa, nitrofurantoin, isoniazid, and halothane). Infants and children: The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:infant test or procedure preparation (birth to 1 year) toddler test or procedure preparation (1 to 3 years) preschooler test or procedure preparation (3 to 6 years) schoolage test or procedure preparation (6 to 12 years) adolescent test or procedure preparation (12 to 18 years) |
| How the test will feel | When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing. |
| Why the test is performed | Serum 5'-N'Tase is measured as an indicator of liver damage resulting primarily from interference with the secretion of bile. Serum 5'-N'Tase is not as sensitive as some other enzymes (for example, ALP , AST , and ALT ) to liver damage, but it is a more liver-specific enzyme . The level of this enzyme parallels alkaline phosphatase (ALP). It is used mostly to differentiate elevations in the above enzymes due to liver damage from damage to skeletal muscle (another cause of elevated ALP, AST and ALT).
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| Normal Values | The normal value is 2 to 17 U/L. Note: U/L = units per liter |
| What abnormal results mean | Greater than normal levels of 5'-N'Tase may indicate:cholestasis (congestion of the biliary system , such as gall stones )hepatic ischemia (inadequate vascularization of the liver) hepaticnecrosis (destruction of liver cells) hepatic tumorhepatitis use of a hepatotoxic drug |
| What the risks are | excessive bleedingfainting or feeling lightheaded hematoma (blood accumulating under the skin) infection (a slight risk any time the skin is broken) multiple punctures to locate veins |
| Special considerations | Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others. |
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