C4P (Lipoprotein(a) – Mass Concentration in Plasma)
This test measures the amount of lipoprotein(a) in your blood plasma. Lipoprotein(a) is a type of cholesterol-related protein that may play a role in heart disease risk.
["Lipoprotein(a) levels can help assess your risk for cardiovascular problems."]
Key facts at a glance
- LOINC
- 43582-6
- Short code
- C4PF
- Synonyms
- C4 Plr-mCnc
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile, leak-proof, screw-cap plastic tube or vacuum collection tube without anticoagulant
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunonephelometry
- CPT
- 86161
- SNOMED
- 39579001
- Specimen volume
- 2-5 mL of pleural fluid
- Stability
- Room temperature: 2 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 300
- TAT
- 24–72 hours
- Order
- routine
What Is Lipoprotein(a)?
Lipoprotein(a), often called Lp(a), is a unique lipoprotein particle that combines cholesterol with a protein called apolipoprotein(a). Unlike other cholesterol types, Lp(a) is inherited and doesn’t change much with diet or exercise. It may contribute to plaque buildup in arteries, increasing the risk of heart attacks or strokes.
Why Might You Need This Test?
Your doctor may order this test if you have a family history of heart disease, high cholesterol, or other conditions linked to artery plaque buildup. It’s also used in some genetic testing or risk assessments for people with certain conditions like aortic valve stenosis.
How Is the Test Done?
A blood sample is drawn from a vein, usually in your arm. The plasma portion is then analyzed to measure the exact amount of lipoprotein(a) present.
What Do Results Mean?
Higher levels of lipoprotein(a) may increase your risk of cardiovascular issues, but results alone don’t diagnose a condition. Your doctor will consider your overall health, other risk factors, and medical history to interpret the results.
Reference range
Reference ranges for complement C4 in pleural fluid are not well-established. Results should be interpreted in conjunction with paired serum complement C4 levels and clinical findings.N/A
No special patient preparation required. Pleural fluid is collected via thoracentesis performed by a qualified healthcare provider.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Lipoprotein(a) [Lp(a)]
Frequently asked questions
Why might my doctor ask for this test?
What are the most common reasons for abnormal results?
Can I lower my lipoprotein(a) levels?
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