Test ID: LDLD
LDL Cholesterol (Beta-Quantification), Serum
NY State Approved 
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Evaluation of cardiovascular risk
Assessment of low-density lipoprotein C (LDL-C) in patients with hypertriglyceridemia, type III hyperlipoproteinemia/dysbetalipoproteinemia, high concentrations of lipoprotein(a), or intermediate-density lipoprotein, and/or when an accurate gold standard determination of LDL-C is required.
Diagnosis of abetalipoproteinemia
Diagnosis of hypobetalipoproteinemia
Method Name A short description of the method used to perform the test
Ultracentrifugation/Selective Precipitation/Enzymatic Colorimetry (Beta-Quantification)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Cholesterol in Low-Density Lipoproteins (LDL)
Cholesterol, DLD (Low-Density Lipoprotein)
Direct LDL (Low-Density Lipoprotein)
LDL (Low-Density Lipoprotein) Cholesterol
LDL Cholesterol (LDLC)
LDL Cholesterol (order if only LDL indicated)
LDL Direct
Low (Low-Density Lipoprotein) Direct
Low-Density Lipoprotein (LDL)
Soft-LDLD
Beta Quant LDL
Abetalipoproteinemia
Hypolipoproteinemia
Familial hypercholesterolemia (FH)
Type III hyperlipoproteinemia/dysbetalipoproteinemia
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:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 3 mL
Collection Instructions: Patient must not consume any alcohol for 24 hours before the specimen is drawn.
Additional Information: Indicate patient's age and sex.
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.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross OK |
| Icterus | Mild OK; Gross reject |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 10 days |
| Frozen | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Low-density lipoprotein cholesterol (LDL-C) is widely recognized as an established cardiovascular risk marker predicated on results from numerous clinical trials that demonstrate the ability of LDL-C to independently predict development and progression of coronary heart disease. In the United States, LDL-C remains the primary focus for cardiovascular risk assessment and evaluation of pharmacologic effectiveness based on treatment target goals. There have been considerable educational efforts invested and directed towards physicians, laboratorians, allied health staff, and the general public regarding LDL-C and strategies to lower LDL-C for reduction of cardiovascular risk.
Low-density lipoproteins are a heterogeneous population of lipid particles classically defined as having a density of 1.006 to 1.063 kg/L obtained by preparative ultracentrifugation. The gold standard beta-quantification (beta-quant or BQ) method combines ultracentrifugation with precipitation and yields a collective quantitative measurement of LDL-C, intermediate-density lipoprotein cholesterol (IDL-C), and lipoprotein(a) cholesterol (Lp(a)-C). In practice, LDL-C is most commonly reported using the Friedewald equation (LDL-C=TC-HDL-TG/5), which yields a fair estimation of LDL-C compared to beta-quantification.
Importantly, there are significant shortcomings and limitations to the Friedewald equation, particularly with the accuracy which require multiple fasting samples to be tested prior to initiation or modification of therapy and recommendations against reporting a calculated LDL-C in patients who are nonfasting, have triglycerides greater than 400 mg/dL, or have type III hyperlipoproteinemia. The equation is particularly inaccurate once the triglycerides are above 200 mg/dL or at low LDL-C concentrations. Furthermore, beta-quantification is an effective method for removal of triglyceride-rich very low- density lipoprotein (VLDL) particles and chylomicrons which often interfere with routine measurement of high-density lipoprotein cholesterol (HDL-C) and calculation of LDL-C.
Homogenous or "direct" LDL-C assays were designed to circumvent the issues with calculating LDL-C in specimens with triglycerides over 400 mg/dL. Clinical laboratories may utilize direct LDL-C assays for that purpose, however recent studies clearly indicate these methods, like lower calculated LDL-C, are unable to adhere to the National Cholesterol Education Program (NCEP) total error goal of <12% for LDL-C and are particularly unsuitable for use in a dyslipidemic population.
There are 2 genetic disorders which cause low LDL-C concentrations, termed abetalipoproteinemia and hypobetalipoproteinemia, and are collectively referred to as familial hypobetalipoproteinemia. Abetalipoproteinemia is a rare recessive disorder caused by a mutation in the MTP gene which encodes for microsomal triglyceride transfer protein. Mutations in MTP result in apolipoprotein B-48 and B-100 deficiencies, which cause impaired absorption of dietary lipids, lipoproteins, and cholesterol in the intestines and a variety of vitamin deficiencies. Individuals will have very low total cholesterol and diminished or absent LDL-C, apolipoprotein B (apoB) and very low-density lipoprotein cholesterol (VLDL-C). Abetalipoproteinemia may be a cause of polyneuropathy.
Hypobetalipoproteinemia is associated with mutations occurring at a variety of genetic loci but primarily involve mutations in the apoB gene. Individuals with hypobetalipoproteinemia exhibit clinical signs and symptoms of intestinal fat malabsorption, hepatosteatosis, and fat soluble vitamin deficiencies although the severity of their symptoms is much less than individuals with abetalipoproteinemia. Patients with hypobetalipoproteinemia have very low concentrations of plasma apoB and LDL-C (<fifth percentile of age- and sex-specific values; LDL-C levels between 25 and 40 mg/dL), as well as decreased VLDL-C concentrations.
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.
The National Cholesterol Education Program (NCEP) has set the following guidelines for LDL-C in adults (ages 18 years and up):
Optimal: <100 mg/dL*
Near optimal: 100-129 mg/dL
Borderline high: 130-159 mg/dL
High: 160-189 mg/dL
Very high: > or =190 mg/dL
*In patients with a history of heart disease and/or diabetes an LDL-C goal of <70 mg/dL should be considered
The National Cholesterol Education Program (NCEP) has set the following guidelines for LDL-C in children and adolescents (ages 2-17 years):
Desirable: <110 mg/dL
Borderline high: 110-129 mg/dL
High: > or =130 mg/dL
Interpretation Provides information to assist in interpretation of the test results
Evaluation of low-density lipoprotein cholesterol (LDL-C)-related cardiovascular risk is based on the following range of values established by the National Cholesterol Education Program (NCEP) in adults (ages 18 years and up):
Optimal: <100 mg/dL*
Near optimal: 100-129 mg/dL
Borderline high: 130-159 mg/dL
High: 160-189 mg/dL
Very high: > or =190 mg/dL
*In patients with a history of heart disease and/or diabetes an LDL-C goal of <70 mg/dL should be considered
The NCEP has set the following guidelines for LDL-C in children and adolescents (ages 2-17 years):
Acceptable: <110 mg/dL
Borderline high: 110-129 mg/dL
High: > or =130 mg/dL
Decreased values may indicate hypobetalipoproteinemia.
Undetectable LDL-C is highly suggestive of abetalipoproteinemia. Related polyneuropathy may exist in affected individuals.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Patients should fast for 12 to 14 hours before the blood is drawn. The patient can take water and prescription drugs if necessary. Alcohol should be avoided for at least 24 hours before specimen draw.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Executive Summary of the 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), JAMA 2001;285:2486-2497
Method Description Describes how the test is performed and provides a method-specific reference
Ultracentrifugation is performed to remove chylomicrons and very low-density lipoproteins present in the supernatant. Separation of low-density lipoprotein particles is achieved via selective precipitation from high-density lipoprotein. Cholesterol is quantitated by an enzymatic, colorometric method.(Ellefson RD, LR, Hodgson PA, Weidman, WH: Cholesterol and triglycerides in serum lipoproteins of young persons in Rochester, Minnesota. Mayo Clinic Proc 1978;53:307-320; Warnick GR, Benderson J, Albers JJ: Dextran sulfate-Mg2+precipitation procedure for quantitation of high-density-lipoprotein cholesterol. Clin Chem 1982;28[6]:1379-1388)
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 Thursday, Saturday; 3 p.m.
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.
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.
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.
83701-Lipoprotein, blood; high resolution fractionation and quantitation of lipoproteins including lipoprotein subclasses when performed (eg, electrophoresis, ultracentrifugation)
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 |
|---|---|---|
| LDLC | LDL Chol (Beta-Quantification), S | 2089-1 |
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