Alkaline Phosphatase ; Raised (Differentials )

Alkaline phosphatase (ALP) is an enzyme that plays a crucial role in various physiological processes in the body. Found primarily in the liver, bone, kidneys, and intestines, ALP is involved in catalyzing the hydrolysis of phosphate esters at a high pH, aiding in processes like bone calcification and phosphate transport in the intestines. The enzyme exists in several isoenzyme forms, with the most clinically relevant being those found in the liver, bone, and kidneys.

Testing for ALP in the blood is significant primarily for diagnosing conditions related to the liver and bone. Elevated levels of ALP are often associated with liver diseases, particularly those that cause blockages in bile flow (cholestasis), such as biliary obstructions from gallstones or tumors, and liver conditions like cirrhosis and hepatitis. High ALP levels can also indicate bone disorders where new bone cells are rapidly being made, such as Paget’s disease or healing fractures.

Clinically, very high ALP levels are frequently seen in patients with cholestasis, either from blockages in the bile ducts outside the liver (extrahepatic) or from liver diseases like primary biliary cholangitis (intrahepatic). These elevations can be severe, sometimes exceeding four times the normal upper limit. Moderate increases in ALP may indicate...