Skip to content

Naphthol AS-BI Phosphate (Alkaline Phosphatase Activity) with Bone Tissue Substrate

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

This test measures the activity of alkaline phosphatase (ALP), an enzyme found in bone and liver cells. It helps assess bone health and metabolism.

Quick summary

["ALP helps identify bone-related conditions and liver function."]

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

Key facts at a glance

LOINC
60624-4
Short code
Na'-Pg'-Ls Skull XR
Synonyms
Na'-Pg'-Ls Skull XR
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr-measured
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 evaluate bone growth, healing, or metabolic processes. It’s often used in diagnosing conditions like osteoporosis, Paget’s disease, or liver issues that can affect ALP levels.

What Does a High or Low Result Mean?

Elevated ALP levels may suggest active bone growth (e.g., in children or during fractures), bone diseases, or liver problems. Lower levels could indicate slower bone development or certain metabolic disorders.

Common Conditions Monitored

This test is commonly used to monitor bone health in conditions like rickets, osteomalacia, or metabolic bone diseases. It may also be checked in patients with suspected liver disease.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the blood draw if your provider specifies it. Bring any medications you’re taking to your appointment.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Bone Alkaline Phosphatase Activity

Frequently asked questions

How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the findings with you during your follow-up visit.
Can I eat or drink before this test?
If fasting is required, avoid food and liquids (except water) for 8–12 hours before the test. If no fasting is needed, you can eat and drink normally.
Does this test interact with any medications?
ALP levels can be influenced by certain medications, such as corticosteroids or anticonvulsants. Always inform your provider about all medications, supplements, or treatments you’re taking.
  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