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Print CPT 80061; 83704
Synonyms
- Cholesterol
- Lipoprotein Analysis (LDL-P, HDL-P, LDL Size), Expanded
Test Details
Turnaround Time
2 - 3 days
Use
NMR LDL-P is a management tool used in appropriate high-risk patients (type 2 diabetes mellitus, metabolic syndrome, CVD risk equivalent, statin-treated patients) to adjudicate response to treatment and guide adjustment in therapy. It is used in conjunction with other lipid measurements and clinical evaluation to aid in the management of lipoprotein disorders associated with cardiovascular disease.
Test Includes
Historical reporting (LDL-P, LDL-C); insulin-resistance score; lipoprotein particle number (LDL-P); particle concentration and size (total HDL-P, small LDL-P, LDL size); standard lipid panel (total cholesterol, calculated LDL cholesterol, HDL cholesterol, triglycerides).
Limitations
If triglyceride level is >800 mg/dL, LDL cholesterol will not be calculated.
Methodology
Nuclear magnetic resonance (NMR)
Note: The NMR method for Triglycerides, unlike the routine chemical method, is not affected by endogenous glycerol, which might be found in very rare clinical conditions such as Hyperglycerolemia (glycerol kinase deficiency-GKD), an X-linked genetic disorder. Large quantitative differences in the chemical and NMR method results may be attributable to high blood glycerol.
Related Documents
For more information, please view the literature below.
Additional Information
The NMR LipoProfile® test is an FDA-cleared blood test that directly measures the amount of LDL circulating in the body. “LDL” is low-density lipoprotein and has long been recognized as a major causal factor in the development of heart disease. Although the relationship of increased LDL particle number and plaque buildup in the artery wall has been known since the 1950s, a diagnostic test did not exist to measure LDL particle number (LDL-P). Historically, LDL cholesterol, or LDL-C, has been used to estimate LDL levels to assess a patient’s LDL-related cardiovascular risk and judge an individual’s response to LDL-lowering therapy. Today, a more reliable measure of LDL exists that directly counts the number of LDL particles a patient has using NMR technology.
Specimen Requirements
Information on collection, storage, and volume
Specimen
Spun NMR LipoTube (preferred), serum from a plain red-top tube, plasma from a lavender-top (EDTA-no gel), or green-top (heparin-no gel) tube. Keep refrigerated and ship with frozen cool packs.
Volume
2 mL
Minimum Volume
1 mL
Container
NMR LipoTube (black-and-yellow-top tube) is the preferred container, plain red-top tube, lavender-top (EDTA-no gel) tube, or green-top (heparin-no gel) tube.
Storage Instructions
Refrigerate all acceptable tube types as soon as possible after centrifugation and within 24 hours of collection. Keep refrigerated prior to shipment, and ship on frozen cool packs. Do not store at room temperature. Do not freeze the sample. Sample is stable refrigerated for six days.
Causes for Rejection
Unspun specimens; plasma/serum contaminated with red cells; citrated plasma (light blue-top tube); gross hemolysis; specimen received in inappropriate container; specimen stored at room temperature for more than a total preanalytical time of 24 hours; specimen more than six days old
Collection
Collect specimen in NMR LipoTube (black-and-yellow-top tube), which is the preferred container. Plain red-top, green-top (heparin-no gel), or lavender-top (EDTA-no gel) tubes are also acceptable. Serum or plasma drawn in gel-barrier collection tubes other than the NMR LipoTube should not be used. The LipoTube is the only acceptable gel-barrier tube. Gently invert tube 8 to 10 times to mix contents and allow specimen to clot for 30 minutes upright at room temperature prior to centrifugation (Plasma tubes should not clot). Centrifuge specimen within two hours of collection at 1800xg for 10 to 15 minutes to separate serum/plasma from the red cells and to avoid red cell contamination during shipment. If the sample cannot be centrifuged immediately, the sample should be refrigerated (at 2ºC to 8ºC) and centrifuged within 24 hours of collection. Note: Centrifuging the specimen while still cold may negatively affect the migration of the gel to the serum/red cell interface and may increase the likelihood of specimens being contaminated with red cells during shipment. All specimens should be centrifuged by the client, prior to shipment to LabCorp, to ensure sample integrity. Do not open NMR LipoTube (black-and-yellow-top). Immediately after centrifugation, pipette separated red-top serum or green-top/lavender-top plasma into a transport tube and label accordingly (serum, heparin plasma, EDTA plasma). Keep samples refrigerated until shipment to the laboratory, and ship with frozen cool packs.