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Naphthol AS-D Phosphatase Activity in Serum (or Plasma)

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

This test measures the activity of an enzyme called naphthol AS-D phosphatase in your blood. Enzymes help speed up chemical reactions in your body, and this one is linked to certain metabolic processes.

Quick summary

["Understanding your enzyme activity can help identify potential metabolic or liver-related health concerns."]

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

Key facts at a glance

LOINC
17806-1
Short code
NAPA Fld-mCnc
Synonyms
NAPA Fld-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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

What Does This Test Measure?

Naphthol AS-D phosphatase is an enzyme that breaks down certain phosphate-containing compounds. Your blood sample is tested to see how effectively this enzyme works. This can be useful in diagnosing conditions affecting metabolism or liver function, though it is less commonly used than other enzyme tests.

Why Might You Need This Test?

This test may be ordered if doctors suspect issues related to phosphate metabolism, certain liver diseases, or conditions affecting enzyme function. It’s sometimes used in research or specialized clinical settings rather than routine care.

What to Expect Before the Test

No special preparation is typically required for this test. You may have a blood draw, and the sample is sent to a lab to measure enzyme activity. Results are usually reported as a ratio or relative activity level compared to a standard.

What to Expect After the Test

After the blood draw, you can resume normal activities. Results are reviewed by your healthcare provider, who will discuss them with you based on your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Naphthol AS-D Phosphatase Test

Frequently asked questions

Why is this test sometimes ordered?
This test may be used in specialized research, genetic studies, or when evaluating rare metabolic disorders that involve enzyme activity. It’s less common in routine medical testing compared to more widely used enzyme tests.
What does a high or low result mean?
Interpretation depends on the clinical context. Your healthcare provider will compare your results to known standards or reference ranges specific to this test. Abnormal results may signal potential issues with phosphate metabolism or enzyme function, but further testing would be needed to clarify.
Is this test painful or uncomfortable?
The blood draw for this test is generally mild discomfort, similar to other routine blood tests. Most people experience only a slight pinch or sting at the venipuncture site, which usually fades quickly. Most patients tolerate it well without complications.
  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