From the Guidelines
An alkaline phosphatase (ALP) level of 889 is significantly elevated and requires immediate medical attention to determine the underlying cause, which could be related to liver or bone disease, as suggested by the American College of Radiology in their 2023 guidelines 1. This elevation is concerning and necessitates a thorough evaluation, including additional laboratory tests such as gamma-glutamyl transferase (GGT) to help differentiate between hepatic and non-hepatic sources of the elevated ALP, as GGT is not found in bone but is present in the liver and other tissues 1. Some key points to consider in the evaluation of elevated ALP include:
- The patient's clinical history and current medications, as some drugs can induce cholestasis and elevate ALP 1
- The possibility of choledocholithiasis, malignant obstruction, or other causes of extrahepatic biliary obstruction if the liver is suspected to be the source of the elevated ALP 1
- The potential for isolated elevated ALP of hepatic origin to suggest a chronic cholestatic process, such as partial bile duct obstruction or primary biliary cholangitis 1 I strongly recommend scheduling an appointment with a healthcare provider as soon as possible for further assessment and guidance, as the elevation of ALP can be associated with serious underlying conditions that require prompt diagnosis and treatment 1.
From the Research
Alkaline Phosphatase
- Alkaline phosphatase (ALP) is a commonly obtained laboratory test, but its diagnostic specificity is limited because it is found in multiple tissues 2.
- The most common cause of ALP elevation is due to underlying malignancy, with 57% of patients having an isolated, elevated ALP of unknown etiology 2.
- Bone disease, unsuspected parenchymal liver disease, non-malignant infiltrative liver disease, and other disorders also account for ALP elevation 2.
- Defective enzyme elimination could play a major role in the pathogenesis of serum alkaline phosphatase elevations 3.
Diagnosis and Interpretation
- Liver function tests, including ALP, are critical in recognizing the presence of liver disease and its specific diagnosis, but the interpretation of the tests may be confusing and difficult 4.
- The evaluation of ALP levels, along with other liver function tests such as GGT, bilirubin, and albumin, can help distinguish between different types of liver disease 5.
- Abdominal ultrasound and serum ALP can be used as screening tests to determine the need for endoscopic retrograde cholangiopancreatography (ERCP) in patients with unexplained abdominal pain 6.
- A normal common bile duct by abdominal ultrasound and normal serum ALP have 100% specificity in excluding bile duct stones 6.
Clinical Significance
- An isolated, elevated ALP of unclear etiology is associated with several specific and important disorders, including metastatic intrahepatic malignancy 2.
- Providers should be aware of the potential clinical significance of an elevated ALP, as it can be a indicator of underlying disease 2.
- The diagnostic workup for an elevated ALP should include a thorough medical history, physical examination, and the appropriate application of non-invasive diagnostic tests 5.