To help evaluate your risk of developing cardiovascular disease (CVD)
LDL Particle Testing (LDL-P)
LDL Particle Testing (LDL-P)
Also Known As
LDL Subclasses
NMR Particle Test
sdLDL
LDL Subfractions
LDL Particle Size or Number
Formal Name
Low-Density Lipoprotein Subfraction Profile
This article was last reviewed
on
This article waslast modified
on April 4, 2018.
At a Glance
Why Get Tested?
When To Get Tested?
When you have a personal and/or family history of CVD at an early age; when the result of your low-density lipoprotein cholesterol (LDL-C) test is within a healthy range, but your healthcare provider thinks that you may have an increased risk of developing heart disease; sometimes to help monitor the effectiveness of lipid-lowering treatment and/or lifestyle changes
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
You may need to fast for 9-12 hours before this test; only water is permitted. Follow any instructions you are given.
Accordion Title
Common Questions
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How is it used?
Low-density lipoprotein particle (LDL particle or LDL-P) testing evaluates LDL particles according to their number, size, density, and/or electrical charge. It may provide useful information for assessing cardiac risk in people who have a personal or family history of heart disease at a young age, especially if their total cholesterol and LDL cholesterol (LDL-C) values are not significantly elevated. LDL subfraction testing is typically done along with or following a lipid profile.
While for many people, the LDL-C test is a good indicator of risk of cardiovascular disease (CVD), research has found that some people with healthy levels of LDL-C still have increased risk of CVD. Similarly, individuals with some chronic conditions such as diabetes may have increased risk even though their LDL-C is at a healthy level. For these populations, it has been suggested that the number of LDL particles and/or their size might be an additional factor to consider when determining their CVD risk. In these cases, lipoprotein subfraction testing may be used to further evaluate an individual's CVD risk.
LDL-P may also be occasionally ordered to monitor the effectiveness of treatment in decreasing the number of small, dense LDL particles (sdLDL).
LDL subfraction testing has been used in clinical settings, while VLDL or HDL subfraction testing is currently used mostly for research purposes. This is because LDL cholesterol has been identified as the primary risk factor for heart disease and more research and development has focused on LDL measurement.
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When is it ordered?
This testing may be ordered as part of an overall evaluation of cardiac risk when someone has a personal or family history of early cardiovascular disease (CVD), especially when the person doesn't have typical cardiac risk factors, such as high cholesterol, high LDL cholesterol, high triglyceride, low HDL cholesterol, smoking, obesity, inactivity, diabetes, and/or hypertension.
When a person with an increased LDL-P and/or a large proportion of small, dense LDL particles has undergone lipid-lowering treatment or lifestyle changes, the healthcare practitioner may order LDL lipoprotein subfraction testing, along with other lipid tests, to monitor the effectiveness of treatment.
Although it is not generally recommended as a screening test, a few healthcare providers are ordering LDL-P along with a battery of other cardiac risk tests when they are attempting to determine someone's overall risk of developing CVD.
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What does the test result mean?
Results of an LDL-P test reflect the method and reporting format used as well as the person's total cholesterol, LDL-C, VLDL, and/or HDL cholesterol. Since different methods separate the subclasses based on different physical properties (particle number, size, density, and/or electrical charge), results may not be directly comparable method to method or laboratory to laboratory.
In general, the result is interpreted within the framework of a lipid profile and its associated risk:
- If a person has a large number of primarily small, dense LDL (sdLDL) and an increased LDL-P, this finding will add to the individual's risk of developing cardiovascular disease above and beyond the risk associated with the total LDL.
- If a person has exclusively large, fluffy LDL and a lower LDL-P, this finding will add no additional risk.
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Is there anything else I should know?
It is important to remember that lipoprotein subfraction and LDL subfraction testing (as well as other lipid and cardiac risk factor testing) is not diagnostic. It attempts to evaluate a person's statistical risk of developing CVD, but it cannot predict the development or severity of disease in a particular person.
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How can I change my LDL subfractions and decrease my LDL-P?
Although there is a genetic component, lipoprotein subfractions and LDL-P can be altered by adopting a diet low in saturated fats, losing excess weight, and exercising regularly. The use of lipid-lowering drugs may also affect the subfraction distribution and LDL-P.
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How long will it take for my results?
It depends on the laboratory performing the test. Not every lab performs LDL-P testing as it requires specialized instruments. Your sample may be sent to a reference laboratory for testing, so it may take several days before results are available.
