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Serum or plasma concentration of alkaline phosphatase (ALP)

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of alkaline phosphatase, an enzyme found in your blood that helps break down certain substances. It can help identify conditions affecting your bones, liver, or intestines.

Quick summary

["ALP levels may signal issues in bone growth, liver function, or intestinal health."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
36059-4
Short code
MR Sacrum
Synonyms
MR Sacrum
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may order an ALP test to check for problems like bone disorders (e.g., rickets, Paget’s disease), liver diseases (e.g., hepatitis, bile duct blockage), or intestinal conditions (e.g., gallstones). It’s also used in monitoring treatments for these conditions or during pregnancy to ensure proper fetal bone development.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood draw from a vein in your arm, or a urine sample (if part of a 24-hour collection). If you’re taking certain medications, let your provider know.

What the Results Mean

Higher ALP levels may indicate liver or bone issues, while lower levels could suggest vitamin D deficiency or certain genetic disorders. Your results will be compared to your baseline and clinical picture for interpretation.

Common Conditions Linked to ALP Levels

Elevated ALP is often seen in liver diseases, bone disorders, or pregnancy. Low ALP might suggest conditions like hypophosphatasia or rare metabolic disorders. Always discuss results with your doctor.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

ALP Level

Frequently asked questions

How often will I need this test?
The frequency depends on your health status. Your doctor may order it once or repeatedly if you have symptoms or ongoing conditions like liver disease, bone pain, or pregnancy.
Can I eat or drink before the test?
For blood tests, you can eat and drink normally. For a 24-hour urine collection, follow your provider’s instructions carefully—usually starting after breakfast and collecting all urine until the next morning.
What if my ALP level is outside the normal range?
If your results are abnormal, your doctor will review them with your full medical history and other test results to determine the cause and next steps, such as further testing or treatment adjustments.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy