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Alkaline phosphatase (ALP) – Indications, Procedure, Results

Last updated: February 8, 2026 Medically reviewed by: RxHarun Orthopedic Specialist Doctor Reading time: 2 min read

Alkaline phosphatase (ALP) is a protein found in all body tissues. Tissues with higher amounts of ALP include the liver, bile ducts, and bone.

A blood test can be done to measure the level of ALP.

A related test is the ALP isoenzyme test .

How the Test is Performed

A blood sample is needed. Most of the time blood is drawn from a vein located on the inside of the elbow or the back of the hand.

How to Prepare for the Test

You should not to eat or drink anything for 6 hours before the test, unless your health care provider tells you otherwise.

Many medicines can interfere with blood test results.

  • Your provider will tell you if you need to stop taking any medicines before you have this test.
  • DO NOT stop or change your medicines without talking to your provider first.

How the Test will Feel

You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.

Why the Test is Performed

Reasons the test may be done include:

  • To diagnose liver or bone disease
  • To check, if treatments for those diseases are working
  • As part of a routine liver function test

Normal Results

The normal range is 44 to 147 IU/L (international units per liter) or 0.73 to 2.45 microkat/L.

Normal values may vary slightly from laboratory to laboratory. They also can vary with age and gender. High levels of ALP are normally seen in children undergoing growth spurts and in pregnant women.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What Abnormal Results Mean

Abnormal results may be due to the following conditions:

Higher-than-normal ALP levels

  • Biliary obstruction
  • Bone conditions
  • Osteoblastic bone tumors , osteomalacia , a fracture that is healing
  • Liver disease or hepatitis
  • Eating a fatty meal if you have blood type O or B
  • Hyperparathyroidism
  • Leukemia
  • Lymphoma
  • Paget disease
  • Rickets
  • Sarcoidosis

Lower-than-normal ALP levels

  • Hypophosphatasia
  • Malnutrition
  • Protein deficiency
  • Wilson disease

Other conditions for which the test may be done:

  • Alcoholic liver disease (hepatitis/cirrhosis)
  • Alcoholism
  • Biliary stricture
  • Gallstones
  • Giant cell (temporal, cranial) arteritis
  • Multiple endocrine neoplasia (MEN) II
  • Pancreatitis
  • Renal cell carcinoma

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area later with a custom field named _rx_references.

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Written by Dr. Harun Ar Rashid, MD - Arthritis, Bones, Joints Pain, Trauma, and Internal Medicine Specialist

Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices. Born and educated in Bangladesh, Dr. Rashid earned his BPT from the University of Dhaka before pursuing postgraduate training internationally. He completed his MD in Internal Medicine at King’s College London, where he developed a special interest in inflammatory arthritis and metabolic bone disease. He then undertook a PhD in Orthopedic Science at the University of Oxford, conducting pioneering research on cytokine signaling pathways in rheumatoid arthritis. Following his doctoral studies, Dr. Rashid returned to clinical work with a fellowship in interventional pain management at the Rx University School of Medicine, refining his skills in image-guided joint injections and minimally invasive pain-relief techniques.