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Alkaline Phosphatase Activity in Serum/Plasma

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

This test measures the activity of the enzyme alkaline phosphatase in your blood, which helps assess liver, bone, and intestinal health.

Quick summary

["ALP helps identify conditions affecting these organs by detecting elevated enzyme levels."]

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

Key facts at a glance

LOINC
73541-5
Short code
Alendronate ind plt IgG SerPl Ql FC
Synonyms
Alendronate ind plt IgG SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
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 Is This Test Done?

Your healthcare provider may order this test to check for liver disease (such as hepatitis or bile duct blockage), bone disorders (like osteoporosis or Paget’s disease), or intestinal issues (such as celiac disease or malabsorption). It can also be part of routine monitoring for conditions like kidney disease or certain cancers.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a liver function panel. Avoid consuming certain medications (like some antibiotics or pain relievers) for 24 hours beforehand if instructed.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but the process is quick and typically painless. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are compared to a baseline or reference range provided by your lab. Elevated levels may suggest liver or bone issues, while low levels could indicate vitamin D deficiency or certain genetic disorders. Your provider will interpret results in the context of your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Alkaline Phosphatase (ALP)

Frequently asked questions

What Are Common Causes of Abnormal Results?
Elevated alkaline phosphatase levels can occur with liver diseases (e.g., cirrhosis, bile duct obstruction), bone diseases (e.g., osteoporosis, fractures), or intestinal conditions (e.g., gallstones, inflammatory bowel disease). Low levels may be linked to vitamin D deficiency, liver disease, or certain medications.
How Often Should This Test Be Done?
Frequency depends on your medical condition. For example, patients with liver disease may need monitoring every few months, while those with bone disorders might have tests annually or as needed. Always follow your provider’s recommendations.
Does This Test Interfere with Other Medications?
Some medications (e.g., certain antibiotics, pain relievers, or thyroid medications) may affect ALP levels. If you’re on long-term treatment, discuss potential interactions with your provider before the test.
  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