Test Details
Methodology
Nuclear magnetic resonance (NMR)
Result Turnaround Time
2 - 3 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
Historical reporting (LDL-P); insulin-resistance score; lipoprotein particle number (LDL-P); particle concentration and size (total HDL-P, small LDL-P, LDL size)
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.
Limitations
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Custom Additional Information
The NMR LipoProfile® test is a 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. The NMR LipoProfile® test reports results for LDL-P, a more reliable measure of LDL that directly counts the number of LDL particles a patient has using NMR technology.
The Lipoprotein Insulin Resistance Index (LP-IR) is a simple, high-throughput means for assessing a patient’s insulin resistance with scores ranging from 0 (most insulin sensitive) to 100 (most insulin resistant).1 LP-IR scores are calculated by combining the weighted measurements of six lipoprotein parameters that are known to be altered in patients with insulin resistance, metabolic syndrome and type 2 diabetes: large VLDL, small LDL, large HDL particle numbers and VLDL, LDL and HDL diameter size.1 LP-IR scores identify individuals at higher risk of developing type 2 diabetes independent of glucose and body mass index.2-4 LP-IR can support early detection and guide lifestyle or treatment strategies aimed at improving insulin sensitivity and reducing diabetes risk. A clinical cutoff of 68 or higher indicates elevated insulin resistance and increased diabetes risk.2
For more references, see Test No. 884095 on the Labcorp Test Menu.
Specimen Requirements
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
Collection Instructions
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 also are 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 eight 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 1600 to 1800 xg 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.
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.
Patient Preparation
Patient should be fasting for eight hours.
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
Footnotes
1. Shalaurova I, Connelly MA, Garvey WT, Otvos JD. Lipoprotein insulin resistance index: a lipoprotein particle-derived measure of insulin resistance. Metab Syndr Relat Disord. 2014 Oct;12(8):422-429. PubMed 24959989
2. Flores-Guerrero JL, Connelly MA, Shalaurova I, et al. Lipoprotein insulin resistance index, a high-throughput measure of insulin resistance, is associated with incident type II diabetes mellitus in the Prevention of Renal and Vascular End-Stage Disease study. J Clin Lipidol. 2019 Jan-Feb;13(1):129-137.e1. PubMed 30591414
3. Dugani SB, Akinkuolie AO, Paynter N, Glynn RJ, Ridker PM, Mora S. Association of Lipoproteins, Insulin Resistance, and Rosuvastatin With Incident Type 2 Diabetes Mellitus : Secondary Analysis of a Randomized Clinical Trial. JAMA Cardiol. 2016 May 1;1(2):136-145. PubMed 27347563
4. Harada PHN, Demler OV, Dugani SB, et al. Lipoprotein insulin resistance score and risk of incident diabetes during extended follow-up of 20 years: The Women's Health Study. J Clin Lipidol. 2017 Sep-Oct;11(5):1257-1267.e2. PubMed 28733174
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 884318 | NMR LipoProfile | 884294 | LDL-P | nmol/L | 54434-6 | |
| 884318 | NMR LipoProfile | 884296 | HDL-P (Total) | umol/L | 49748-7 | |
| 884318 | NMR LipoProfile | 884297 | Small LDL-P | nmol/L | 43727-7 | |
| 884318 | NMR LipoProfile | 884309 | LDL Size | nm | 17782-4 | |
| 884318 | NMR LipoProfile | 884312 | LP-IR Score | 62255-5 | ||
| 884318 | NMR LipoProfile | 884310 | N/A | |||
| 884318 | NMR LipoProfile | 123469 | Historical Reporting | N/A | ||
| Order Code | 884318 | |||||
| Order Code Name | NMR LipoProfile | |||||
| Order Loinc | ||||||
| Result Code | 884294 | |||||
| Result Code Name | LDL-P | |||||
| UofM | nmol/L | |||||
| Result LOINC | 54434-6 | |||||
| Order Code | 884318 | |||||
| Order Code Name | NMR LipoProfile | |||||
| Order Loinc | ||||||
| Result Code | 884296 | |||||
| Result Code Name | HDL-P (Total) | |||||
| UofM | umol/L | |||||
| Result LOINC | 49748-7 | |||||
| Order Code | 884318 | |||||
| Order Code Name | NMR LipoProfile | |||||
| Order Loinc | ||||||
| Result Code | 884297 | |||||
| Result Code Name | Small LDL-P | |||||
| UofM | nmol/L | |||||
| Result LOINC | 43727-7 | |||||
| Order Code | 884318 | |||||
| Order Code Name | NMR LipoProfile | |||||
| Order Loinc | ||||||
| Result Code | 884309 | |||||
| Result Code Name | LDL Size | |||||
| UofM | nm | |||||
| Result LOINC | 17782-4 | |||||
| Order Code | 884318 | |||||
| Order Code Name | NMR LipoProfile | |||||
| Order Loinc | ||||||
| Result Code | 884312 | |||||
| Result Code Name | LP-IR Score | |||||
| UofM | ||||||
| Result LOINC | 62255-5 | |||||
| Order Code | 884318 | |||||
| Order Code Name | NMR LipoProfile | |||||
| Order Loinc | ||||||
| Result Code | 884310 | |||||
| Result Code Name | ||||||
| UofM | ||||||
| Result LOINC | N/A | |||||
| Order Code | 884318 | |||||
| Order Code Name | NMR LipoProfile | |||||
| Order Loinc | ||||||
| Result Code | 123469 | |||||
| Result Code Name | Historical Reporting | |||||
| UofM | ||||||
| Result LOINC | N/A |