Which laboratory finding might suggest the presence of bile duct obstruction?

Elevated alkaline phosphatase (ALP) is strongly associated with bile duct obstruction. ALP is an enzyme found primarily in the liver, bones, kidneys, and bile ducts. When there is an obstruction in the bile ducts, such as due to stones, strictures, or tumors, the normal flow of bile is disrupted. This disruption causes an accumulation of substances that should be cleared, including alkaline phosphatase itself, leading to higher levels in the bloodstream.

In cases of bile duct obstruction, other laboratory markers can also be affected, but elevated ALP is a key indicator. It often forms part of a group of liver function tests that help to assess the functionality of the liver and biliary system. Elevated ALP alone may not definitively diagnose bile duct obstruction, but when seen with other symptoms and findings, it strongly suggests the possibility.

The other options do not serve as effective indicators of bile duct obstruction. Decreased bilirubin levels would suggest a lack of biliary obstruction, commonly seen in healthy individuals. Low protein levels can be indicative of liver dysfunction but are not specific for bile duct issues. High cholesterol levels might be present in various conditions, but they do not directly point to bile duct obstruction. The distinctive rise in ALP