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Serum/plasma mass concentration of placental alkaline phosphatase (PLAP)

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

This test measures the amount of placental alkaline phosphatase, an enzyme produced primarily by the placenta during pregnancy. It may be checked to assess placental function or detect certain conditions.

Quick summary

["PLAP helps evaluate placental health or identify potential pregnancy complications."]

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

Key facts at a glance

LOINC
47900-6
Short code
GH 20M p TRH SerPl-aCnc
Synonyms
GH 20M p TRH SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85610
SNOMED
396252006
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 a PLAP test if you’re pregnant and experiencing symptoms like excessive bleeding, pain, or signs of placental issues. It can also be used in non-pregnant individuals to investigate conditions affecting enzyme levels, such as liver disease or certain cancers.

What Does a PLAP Test Measure?

PLAP is an enzyme found in high levels in the placenta during pregnancy. Outside of pregnancy, its presence may indicate abnormal cell activity, such as in tumors or liver disorders. The test measures its concentration in your blood serum or plasma.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum or plasma for testing. This test does not require fasting.

What Are Possible Results?

Results are reported as a mass concentration (e.g., units per milliliter or gram per liter). Interpretation depends on clinical context, including your medical history and symptoms. Elevated levels may suggest placental issues or other conditions, while lower levels may indicate normal or reduced placental function.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: serum

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

PLAP Level

Frequently asked questions

What Does It Mean If My PLAP Level Is High?
High PLAP levels during pregnancy can signal placental abnormalities, such as placental insufficiency or preeclampsia. In non-pregnant individuals, elevated PLAP may be linked to liver disease, certain cancers (e.g., liver or pancreatic tumors), or other metabolic conditions. Always discuss results with your provider.
What Does It Mean If My PLAP Level Is Low?
Low PLAP levels during pregnancy may suggest reduced placental function or early pregnancy loss. Outside pregnancy, low levels could indicate normal enzyme activity or conditions affecting enzyme production, such as liver disease in its early stages. Your provider will consider your full clinical picture.
How Often Should I Get This Test?
The frequency depends on your medical needs. Pregnant individuals may receive PLAP testing if high-risk for placental issues. Non-pregnant individuals may get it only if symptoms or lab findings suggest a need, such as unexplained enzyme abnormalities.
  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