Placental Alkaline Phosphatase (PLAP) Test
This is a lab test that measures levels of placental alkaline phosphatase (PLAP), a protein made by the placenta during pregnancy that can also point to certain types of tumors or pregnancy-related conditions.
{"PLAP is normally produced during pregnancy but may appear in blood with certain tumors","Mainly used to monitor germ cell tumors and some other cancers","Results are reported as positive or negative, with levels possibly measured","Your healthcare provider will interpret results based on your specific condition"}
Key facts at a glance
- LOINC
- 10458-8
- Short code
- ALP-PLAC-TS
- Synonyms
- ALP Plac Ag Tiss Ql ImStn
- Category
- chemistry
- Sample
- serum
- Container
- Tissue container with formalin (10% neutral buffered formalin) for fixation
- Units
- not specified
- Ref low
- 44
- Ref high
- 147
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 18 years
- Method
- immune-stain
- CPT
- 88342
- SNOMED
- 708188004
- Specimen volume
- Tissue sample adequate for IHC processing (typically 3-5 mm thickness)
- Stability
- Formalin-fixed tissue stable at room temperature for 24-48 hours; paraffin-embedded blocks stable for years
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The placental alkaline phosphatase (PLAP) test detects the presence of a specific protein called placental alkaline phosphatase in your blood or tissue. This protein is normally produced by the placenta during pregnancy, which is why it's called 'placental' alkaline phosphatase.
Why might I need this test?
Your doctor may order this test if they suspect certain types of tumors, particularly germ cell tumors (which can affect the ovaries, testicles, or other areas), or other cancers. It may also be used to monitor how well treatment is working or to check if cancer has returned. During pregnancy, it may be used to assess certain placental conditions.
What happens during the test?
A healthcare professional will take a blood sample from a vein in your arm. The procedure only takes a few minutes. For tissue testing (immunohistochemistry), a tissue sample would be collected through a biopsy procedure, which your doctor will explain in detail.
Are there any risks?
Blood tests carry minimal risks, including slight bruising at the needle site, fainting, or rare infection. Tissue biopsy carries additional risks specific to the procedure location, which your doctor will discuss with you.
Reference range
Adult: 44-147 U/Lnot specified
No special patient preparation; fresh or formalin-fixed tissue specimen required
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated PLAP levels may indicate: germ cell tumors (ovarian, testicular, mediastinal), certain lung cancers, other malignancies, or in rare cases, non-cancerous conditions. During pregnancy, abnormal levels may suggest placental problems. A positive result does not definitively mean cancer—your doctor will correlate results with other clinical findings, imaging studies, and your overall health status for proper diagnosis.
Frequently asked questions
Do I need to fast before this test?
How long does it take to get results?
Can PLAP levels be high without cancer?
Will my insurance cover this test?
Sources
- 1
- 2LOINC - 10458-8Source
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.
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