This membrane-bound enzyme of the liver is increased in diseases of the liver, particularly if the hepatobiliary tract is involved. The appearance of 5 " ²-NT in serum is due to cholestasis, and its significance is similar to that of ALP and GGT. However, 5 " ²-NT is not as subject to drug induction as GGT and ALP, and it is not subject to confusion with alternate sources of the enzyme, as is seen with ALP.
Normal range: 2.0 " “8.0 U/L.
Use
Determining cholestatic liver disease, particularly when GGT and ALP could be falsely elevated due to drug induction
Better test for secondary tumors and lymphomas of the liver than ALP
Interpretation
Increased In
5 " ²-NT is increased in the following conditions:
Hepatobiliary disease with intrahepatic or extrahepatic biliary obstruction
Hepatic carcinoma
Early biliary cirrhosis
Pregnancy (third semester)
Inflammatory arthritis
Limitations
5 " ²-NT can be elevated in hyperammonemia due to analytical interference.
Normal in pregnancy and postpartum period (in contrast to serum leucine aminopeptidase and ALP).