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Small Dense LDL (sdLDL)
Test CodesdLDL
Quest Code
36406
CPT Codes
83722
Preferred Specimen
1 mL serum
Patient Preparation
Fasting may be required for this test. Please ask your doctor if you should fast prior to testing.
Minimum Volume
0.2 mL
Instructions
1. Collect and label sample according to standard protocols.
2. Gently invert tube 5 times immediately after draw. DO NOT SHAKE.
3. Allow blood to clot for 30 minutes.
4. Centrifuge for 10 minutes.
5. Store and transport refrigerated.
Special Instructions: At least 3 mL of blood should be drawn.
2. Gently invert tube 5 times immediately after draw. DO NOT SHAKE.
3. Allow blood to clot for 30 minutes.
4. Centrifuge for 10 minutes.
5. Store and transport refrigerated.
Special Instructions: At least 3 mL of blood should be drawn.
Transport Temperature
Refrigerated (cold packs)
Specimen Stability
Room temperature: Unacceptable
Refrigerated: 10 days
Frozen -20° C: 14 days
Frozen -70° C: 90 days
Refrigerated: 10 days
Frozen -20° C: 14 days
Frozen -70° C: 90 days
Methodology
Enzymatic
Setup Schedule
Set up: Mon-Sat; Report available: 3 days
Reference Range
<50.0 mg/dL
Clinical Significance
Although low-density lipoprotein cholesterol (LDL-C) is a well-known risk factor for cardiovascular disease (CVD), LDL is not homogeneous and comprises particles with varying size and atherogenic properties. Of these particles, a subset known as small, dense LDL (sdLDL) is emerging as the most important CVD risk factor.[1,2] Because of their biophysical properties, sdLDL particles are more atherogenic than other LDL particles, lipoproteins, and triglycerides.[3]
This test measures sdLDL particle abundance,[4,5] which is associated with risk of incident CVD (including coronary heart disease [CHD], heart attack, and stroke). In a meta- analysis of studies comparing high vs low sdLDL, people with high sdLDL had over 1.3-fold higher risk (odds ratio, 1.36; 95% CI, 1.21-1.52) for incident CHD compared to those with low sdLDL.[6] Among the offspring of participants in the Framingham Heart Study, elevated sdLDL-C was reported as the best lipid measure of incident CVD risk at 10-year follow-up (hazard ratio, 1.42; 95% CI, 1.21-1.68).[3] Furthermore, sdLDL-C is associated with risk of incident CHD regardless of LDL-C levels.[7,8] sdLDL-C is also more closely correlated with CHD [3] and carotid intima-media thickness (a measure of atherosclerosis) than is LDL-C.[9]
Individuals suitable for testing include those who may benefit from refinement of CVD risk assessment.
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Third report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Circulation. 2002;106(25):3143-3421
2. Handelsman Y, et al. Endocr Pract. 2020;26(10):1196-1224.
3. Ikezaki H, et al. J Am Heart Assoc. 2021;10(5):e019140.
4. Ito Y, et al. Clin Chem. 2011;57(1):57-65.
5. Hirano T, et al. J Lipid Res. 2003;44(11):2193-2201.
6. Liou L, Kaptoge S. PLoS One. 2020;15(11):e0241993.
7. Hoogeveen RC, et al. Arterioscler Thromb Vasc Biol. 2014;34(5):1069-1077.
8. Tsai MY, et al. Arterioscler Thromb Vasc Biol. 2014;34 (1):196-201.
9. Ikezaki H, et al. J Atheroscler Thromb. 2020;27(10): 1108-1122.
This test measures sdLDL particle abundance,[4,5] which is associated with risk of incident CVD (including coronary heart disease [CHD], heart attack, and stroke). In a meta- analysis of studies comparing high vs low sdLDL, people with high sdLDL had over 1.3-fold higher risk (odds ratio, 1.36; 95% CI, 1.21-1.52) for incident CHD compared to those with low sdLDL.[6] Among the offspring of participants in the Framingham Heart Study, elevated sdLDL-C was reported as the best lipid measure of incident CVD risk at 10-year follow-up (hazard ratio, 1.42; 95% CI, 1.21-1.68).[3] Furthermore, sdLDL-C is associated with risk of incident CHD regardless of LDL-C levels.[7,8] sdLDL-C is also more closely correlated with CHD [3] and carotid intima-media thickness (a measure of atherosclerosis) than is LDL-C.[9]
Individuals suitable for testing include those who may benefit from refinement of CVD risk assessment.
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Third report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Circulation. 2002;106(25):3143-3421
2. Handelsman Y, et al. Endocr Pract. 2020;26(10):1196-1224.
3. Ikezaki H, et al. J Am Heart Assoc. 2021;10(5):e019140.
4. Ito Y, et al. Clin Chem. 2011;57(1):57-65.
5. Hirano T, et al. J Lipid Res. 2003;44(11):2193-2201.
6. Liou L, Kaptoge S. PLoS One. 2020;15(11):e0241993.
7. Hoogeveen RC, et al. Arterioscler Thromb Vasc Biol. 2014;34(5):1069-1077.
8. Tsai MY, et al. Arterioscler Thromb Vasc Biol. 2014;34 (1):196-201.
9. Ikezaki H, et al. J Atheroscler Thromb. 2020;27(10): 1108-1122.
Performing Laboratory
Cleveland HeartLab, Inc
6701 Carnegie Avenue Suite 500
Cleveland, OH 44103-4623
