Alpboneserplmcnc
A blood test that measures the bone-specific form of alkaline phosphatase, an enzyme produced by bone-forming cells.
{"Bone alkaline phosphatase is a marker of bone formation","It helps diagnose and monitor bone diseases like osteoporosis and Paget's disease","Higher levels are normal in growing children and pregnant women","The test uses a blood sample taken from a vein in your arm","Results are often compared with total alkaline phosphatase for better interpretation"}
Key facts at a glance
- LOINC
- 17838-4
- Short code
- Bone ALP; B-ALP; bone-specific alkaline phosphatase
- Synonyms
- ALP Bone SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or plain red-top tube; plasma acceptable in lithium heparin or EDTA tubes depending on analyzer requirements
- Units
- not specified
- Ref low
- 4.5
- Ref high
- 22.9
- Critical range
- — – 200 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Colorimetric enzymatic assay using p-nitrophenyl phosphate (pNPP) substrate or similar chromogenic substrate; may also use electrophoretic separation or immunoassay for bone-specific isoenzyme detection
- CPT
- 82150 (Alkaline phosphatase, total) or 82146 (Alkaline phosphatase, isoenzyme)
- SNOMED
- 271587006 (Bone alkaline phosphatase measurement) or 313295009 (Serum alkaline phosphatase measurement)
- Specimen volume
- 1.0 mL minimum serum/plasma; 2.0-3.0 mL preferred for optimal testing
- Stability
- Room temperature: 2-3 days; Refrigerated (2-8°C): 5-7 days; Frozen (-20°C or below): several weeks to months. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 50
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The bone alkaline phosphatase test measures the amount of bone-specific alkaline phosphatase (B-ALP) in your blood. Alkaline phosphatase (ALP) is an enzyme found throughout your body, but this test specifically looks at the form that comes from bone-forming cells called osteoblasts. When bones are being actively formed or remodeled, these cells release bone alkaline phosphatase into the bloodstream.
Why is it done?
This test is primarily ordered to evaluate bone health and activity. Healthcare providers use it to check for conditions that affect bone metabolism, such as Paget's disease (a condition causing abnormal bone growth), osteoporosis (bone thinning), bone cancer, or hyperparathyroidism (overactive parathyroid glands). It can also help distinguish between bone-related and liver-related causes when total alkaline phosphatase is elevated.
How to prepare
Typically, no special preparation is needed for this test. However, your doctor may ask you to fast for a certain period before the blood draw. It's important to inform your healthcare provider about any medications, vitamins, or supplements you're taking, as some drugs can affect test results. Routine blood tests can usually be done at any time of day without fasting.
What happens during the test
A healthcare professional will clean the skin on your arm with an antiseptic wipe and place a flexible band (tourniquet) around your upper arm to make your veins more visible. Then, a needle will be inserted into a vein, and blood will be collected into a vial or tube. You may feel a brief pinch or sting. The entire process usually takes less than five minutes. After the blood is drawn, the needle is removed, and pressure is applied to stop any bleeding.
Understanding your results
Normal bone alkaline phosphatase levels vary depending on age, sex, and the laboratory that performs the test. Generally, adults have lower levels than children and adolescents because bone growth slows after puberty. Elevated levels may indicate increased bone turnover from conditions like Paget's disease, bone metastases, osteomalacia, or fractures. Your doctor will interpret your results in context with your overall health, symptoms, and possibly other test results.
Are there any risks?
The risks associated with this blood test are minimal. You may experience slight bruising, bleeding, or dizziness during or after the procedure. In rare cases, infection can occur at the puncture site. These side effects are usually temporary and resolve quickly. If you have a bleeding disorder or take blood-thinning medications, inform your healthcare provider before the test.
Reference range
4.5-22.9 μg/Lnot specified
No fasting required; morning collection preferred due to diurnal variation
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
What is the difference between total alkaline phosphatase and bone alkaline phosphatase?
Do I need to fast before this test?
What can cause elevated bone alkaline phosphatase?
How often should this test be repeated?
Can lifestyle affect bone alkaline phosphatase levels?
Sources
- 1
- 2
- 3
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 10, 2026. · Read our editorial policy