LDL Receptor-Related Protein 4 Antibody Titer, Serum
A blood test that measures antibodies against LRP4, a protein involved in communication between the nervous and immune systems.
["Anti-LRP4 antibodies may help support an evaluation for certain forms of autoimmune myasthenia gravis."]
Key facts at a glance
- LOINC
- 108286-6
- Short code
- LDL recep related protein 4 Ab Titr Ser
- Synonyms
- LDL recep related protein 4 Ab Titr Ser
- Category
- lipid
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 100
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 83721
- SNOMED
- 113079007
- 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 is this test?
This test measures the level of antibodies directed against low-density lipoprotein receptor-related protein 4, also called LRP4, in a blood sample. LRP4 helps the immune system communicate with the muscles at the neuromuscular junction.
Why might I need this test?
The test may be used as part of an evaluation for myasthenia gravis, an autoimmune condition that can cause muscle weakness. It is usually considered when symptoms suggest the condition but other antibody tests have not provided a clear answer.
How is the test performed?
A blood sample is collected, and the serum is separated and tested for anti-LRP4 antibodies. The laboratory may use an immunoassay, but the specific method depends on the laboratory performing the test.
How do I prepare for the test?
Fasting is generally not required for this test. Tell your healthcare professional if you have an autoimmune disease, are taking immune-system medicines, or have recently received certain antibody treatments, because these may affect interpretation.
Reference range
Optimal: <100 mg/dLN/A
Fasting for 12-14 hours preferred. Water is permitted. Avoid alcohol for 24 hours before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Detectable anti-LRP4 antibodies may support the presence of an autoimmune neuromuscular-junction disorder such as myasthenia gravis. A positive result does not establish the diagnosis by itself and must be interpreted with symptoms, examination findings, and other antibody tests. A negative result does not completely exclude myasthenia gravis because some affected patients do not have these antibodies.
Short name
Anti-LRP4 antibody titer
Frequently asked questions
What are anti-LRP4 antibodies?
Does a positive result mean I have myasthenia gravis?
Can I take medicines before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 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 16, 2026. · Read our editorial policy