LDL Particle Concentration NMR, Plasma
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Assessment and management of a patient's risk for cardiovascular disease and events
Nuclear Magnetic Resonance (NMR)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
LDL Particles NMR, P
LDL particle number
LDL particle concentration
Nuclear magnetic resonance
LDL particle concentration
Nuclear magnetic resonance
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube: Lavender top (EDTA)
Specimen Volume: 1 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Mild OK; Gross reject
Mild OK; Gross reject
Mild OK; Gross reject
Plasma/serum gel tube
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Plasma EDTA||Refrigerated (preferred)||6 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The key role of apolipoprotein B (apoB) particles in the pathogenesis of cardiovascular disease is well recognized. A majority (90%-95%) of these apoB particles are low-density lipoprotein particles. While low-density lipoprotein cholesterol (LDL-C) remains the primary focus for cardiovascular risk assessment and evaluation of pharmacologic effectiveness based on treatment target goals, evidence indicates that a narrow focus on LDL-C assessment and treatment alone is not the optimal strategy for patient care. What remains controversial is whether we are using the best measure of LDL to identify all individuals at risk and further stratify those who would benefit from additional or more aggressive therapeutic interventions.
There are several known limitations that make LDL-C a less accurate marker of cardiovascular risk than either non-high-density lipoprotein cholesterol (non-HDL-C), low-density lipoprotein particle number (LDL-P), or apoB. Furthermore, there is sufficient evidence that other triglyceride-rich lipoproteins (TRL) are atherogenic including very low-density lipoprotein (VLDL) remnants and intermediate-density lipoproteins (IDL). There continue to be numerous patients who succeed in meeting their target "LDL-C goal" but still develop complications from atherosclerotic vascular disease and suffer from cardiovascular events. These patients bear the burden of having residual risk not identified with traditional metabolic and cardiovascular markers.
Several studies have shown that quantitative measures of LDL particle concentrations, assessed by either nuclear magnetic resonance (NMR) or apolipoprotein B, are associated with cardiovascular disease to a much greater extent than either LDL size or LDL-C. This is due to the 1:1 relationship of apoB to non-HDL particles, meaning there is 1 apoB per LDL, IDL, Lp(a), VLDL, and chylomicron particles. The numbers of atherogenic LDL particles are frequently elevated even though LDL cholesterol is not, particularly in patients with prediabetes, diabetes, or insulin sensitivity. In the Veterans Affairs High Density Lipoprotein Intervention Trial, which included a relatively large proportion of subjects with diabetes (30.4%) and insulin resistance (30%), both traditional risk factors and NMR analyses were assessed in patients treated with the lipid-modifying agent gemfibrozil or placebo. LDL cholesterol was not influenced by treatment with gemfibrozil, but HDL cholesterol increased by 6% and was associated with a 22% reduction in events. While LDL cholesterol remained unchanged, the total LDL particle concentration decreased by 5%, small LDL particle concentration decreased by 20%, total HDL particle concentration increased by 10%, and large HDL particles increased by 21%. Interestingly, neither baseline nor on-trial concentrations of HDL cholesterol, LDL cholesterol, or triglycerides were significant predictors of coronary heart disease (CHD) events. Among NMR lipoproteins measured, both baseline and on-trial concentrations of total LDL and HDL particle concentrations were independent predictors of new CHD events with on-trial p-values of 0.0003 and <0.0001, respectively. Neither LDL nor HDL particle size was related to CHD events.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
TOTAL LDL PARTICLE CONCENTRATION
< or =15 years: not established
Adults (> or =16 years):
<1,000 nmol/L (optimal)
1,000-1,299 nmol/L (near or above optimal)
1,300-1,599 nmol/L (borderline high)
1,600-2,000 nmol/L (high)
>2,000 nmol/L (very high)
Interpretation of LDL lipoprotein concentration should be conducted within the context of standard lipid profile results (total cholesterol, triglycerides, HDL cholesterol, calculated LDL cholesterol and non-HDL cholesterol).
Elevated total LDL particle concentration is associated with increased atherogenic particles and subsequent cardiovascular risk.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Blake GJ, Otvos JD, Rifai N, Ridker PM: Low-density lipoprotein particle concentration and size as determined by nuclear magnetic resonance spectroscopy as predictors of cardiovascular disease in women. Circulation 2002;106(15):1930-1937
2. Rosenson RS, Otvos JD, Freedman DS: Relations of lipoprotein subclass levels and low-density lipoprotein size to progression of coronary artery disease in the Pravastatin Limitation of Atherosclerosis in the Coronary Arteries (PLAC-I) trial. Am J Cardiol 2002;90(2):89-94
3. Kuller L, Arnold A, Tracy R, et al: Nuclear magnetic resonance spectroscopy of lipoproteins and risk of coronary heart disease in the cardiovascular health study. Arterioscler Thromb Vasc Biol 2002;22(7):1175-1180
4. Cole TG, Contois JH, Csako G, et al: Association of Apolipoprotein B and Nuclear Magnetic Resonance Spectroscopy-Derived LDL Particle Number with Outcomes in 25 Clinical Studies: Assessment by the AACC Lipoprotein and Vascular Diseases Division Working Group on Best Practices. Clin Chem 2013;59(5): online
5. Otvos JD, Collins D, Freedman DS, et al: Low-density lipoprotein and high-density lipoprotein particle subclasses predict coronary events and are favorably changed by gemfibrozil therapy in the Veterans Affairs High-Density Lipoprotein Intervention Trial. Circulation 2006;113(12):1556-1563
Method Description Describes how the test is performed and provides a method-specific reference
LDL particle concentrations are measured using an automated nuclear magnetic resonance (NMR) spectrometer. Lipoproteins are analyzed by the NMR according to the spectral signals produced by the terminal methyl groups contained within the lipid particles. The number of methyl groups present on triglycerides, cholesterol, cholesteryl esters, and phospholipids is consistent for particles at a given size, allowing for translation into particle concentration. Individual subclasses are derived using the measured amplitude of the NMR signal along with a deconvolution algorithm. The total LDL-P concentration is the sum of all LDL particle subfractions/sizes and is inclusive of IDL and Lp(a). NMR lipoprotein analyses have been evaluated against other existing methods of lipoprotein subclass methodologies; however, there are no standardization programs targeted towards these analytes.(Otvos JD: Measurement of lipoprotein subclass profiles by nuclear magnetic resonance spectroscopy. Clin Lab 2002;48:171-180; Jeyarajah EJ, Cromwell WC, Otvos JD: Lipoprotein particle analysis by nuclear magnetic resonance spectroscopy. Clin Lab Med 2006;26:847-870; Freedman DS, Otvos JD, Jeyarajah EJ, et al: Sex and age differences in lipoprotein subclasses measured by nuclear magnetic resonance spectroscopy: the Framingham Study. Clin Chem 2004;50:1189-1200)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; Continuous
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Same day/5 days
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
83704-quantitation of lipoprotein particle numbers and lipoprotein particle subclasses (eg, by nuclear magnetic resonance spectroscopy)
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|LDLPV||Total LDL Particle Concentration||14815-5|