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ver·y-low-den·si·ty lip·o·pro·tein(VLDL) (ver'ē-lō-den'si-tē lip'ō-prō'tēn)
A complex of protein and lipid in which the lipid content exceeds the protein content.
Synonym/acronym: Lipid fractionation; lipoprotein phenotyping; 3ga1-lipoprotein cholesterol, high-density lipoprotein (HDL); β-lipoprotein cholesterol, low-density lipoprotein (LDL); pre-β-lipoprotein cholesterol, very-low-density lipoprotein (VLDL).
To assist in categorizing lipoprotein as an indicator of cardiac health.
SpecimenSerum (3 mL) collected in a gold-, red-, or red/gray-top tube.
(Method: Electrophoresis and 4°C test for specimen appearance) There is no quantitative interpretation of this test. The specimen appearance and electrophoretic pattern is visually interpreted.
|Hyperlipoproteinemia: Fredrickson Type||Specimen Appearance||Electrophoretic Pattern|
|Type I||Clear with creamy top layer||Heavy chylomicron band|
|Type IIa||Clear||Heavy β band|
|Type IIb||Clear or faintly turbid||Heavy β and pre-β bands|
|Type III||Slightly to moderately turbid||Heavy β band|
|Type IV||Slightly to moderately turbid||Heavy pre-β band|
|Type V||Slightly to moderately turbid with creamy top layer||Intense chylomicron band and heavy β and pre-β bands|
Lipoprotein electrophoresis measures lipoprotein fractions to determine abnormal distribution and concentration of lipoproteins in the serum, an important risk factor in the development of coronary artery disease (CAD). The lipoprotein fractions, in order of increasing density, are (1) chylomicrons, (2) very-low-density lipoprotein (VLDL), (3) low-density lipoprotein (LDL), and (4) high-density lipoprotein (HDL). Chylomicrons and VLDL contain the highest levels of triglycerides and lower amounts of cholesterol and protein. LDL and HDL contain the lowest amounts of triglycerides and relatively higher amounts of cholesterol and protein. Studies have shown that CAD is inversely related to LDL cholesterol (LDLC) particle size. An electrophoretic pattern demonstrating the presence of small, dense LDL particles (non-A) carries a threefold risk for developing CAD over the presence of larger, more buoyant LDLC particles (pattern A).
This procedure is contraindicated for
- Evaluate known or suspected disorders associated with altered lipoprotein levels
- Evaluate patients with serum cholesterol levels greater than 250 mg/dL, which indicate a high risk for CAD
- Evaluate the response to treatment for high cholesterol and determine the need for drug therapy
Potential diagnosisType I: Hyperlipoproteinemia, or increased chylomicrons, can be primary resulting from an inherited deficiency of lipoprotein lipase or secondary caused by uncontrolled diabetes, systemic lupus erythematosus, and dysgammaglobulinemia. Total cholesterol is normal to moderately elevated, and triglycerides (mostly exogenous chylomicrons) are grossly elevated. If the condition is inherited, symptoms will appear in childhood. Type IIa: Hyperlipoproteinemia can be primary resulting from inherited characteristics or secondary caused by uncontrolled hypothyroidism, nephrotic syndrome, and dysgammaglobulinemia. Total cholesterol is elevated, triglycerides are normal, and LDLC is elevated. If the condition is inherited, symptoms will appear in childhood. Type IIb: Hyperlipoproteinemia can occur for the same reasons as in type IIa. Total cholesterol, triglycerides, and LDLC are all elevated. Type III: Hyperlipoproteinemia can be primary resulting from inherited characteristics or secondary caused by hypothyroidism, uncontrolled diabetes, alcoholism, and dysgammaglobulinemia. Total cholesterol and triglycerides are elevated, whereas LDLC is normal. Type IV: Hyperlipoproteinemia can be primary resulting from inherited characteristics or secondary caused by poorly controlled diabetes, alcoholism, nephrotic syndrome, chronic renal failure, and dysgammaglobulinemia. Total cholesterol is normal to moderately elevated, triglycerides are moderately to grossly elevated, and LDLC is normal. Type V: Hyperlipoproteinemia can be primary resulting from inherited characteristics, or secondary caused by uncontrolled diabetes, alcoholism, nephrotic syndrome, and dysgammaglobulinemia. Total cholesterol is normal to moderately elevated, triglycerides are grossly elevated, and LDLC is normal.
- Failure to follow usual diet for 2 wk before the test can yield results that do not accurately reflect the patient’s cholesterol values.
- Ingestion of alcohol 24 hr before the test, ingestion of food 12 hr before the test, and excessive exercise 12 hr before the test can alter results.
- Numerous drugs can alter results (see monographs titled “Cholesterol, Total” and “Triglycerides”).
- Failure to follow dietary restrictions before the procedure may cause the procedure to be canceled or repeated.
Nursing Implications and Procedure
- Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
- Patient Teaching: Inform the patient this test can assist in evaluating cardiac health.
- Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
- Obtain a history of the patient’s cardiovascular system, risk for heart disease, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
- Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values).
- Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
- Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
- Instruct the patient to follow his or her usual diet for 2 wk before testing.
- Instruct the patient to fast and to avoid excessive exercise for at least 12 hr before testing and to refrain from alcohol consumption for 24 hr before testing.
- Note that there are no medication restrictions unless by medical direction.
- Potential complications:
- Ensure that the patient has complied with dietary and activity restrictions as well as other pretesting preparations; assure that food, fluids, and activity have been restricted for at least 12 hr and that alcohol has been restricted for at least 24 hr prior to the procedure.
- Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
- Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
- Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
- Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
- Promptly transport the specimen to the laboratory for processing and analysis.
- Inform the patient that a report of the results will be made available to the requesting health-care provider (HCP), who will discuss the results with the patient.
- Instruct the patient to resume usual diet, fluids, and activity, as directed by the HCP.
- Nutritional Considerations: Abnormal lipoprotein electrophoresis patterns may be associated with cardiovascular disease. Nutritional therapy is recommended for the patient identified to be at risk for developing CAD or for individuals who have specific risk factors and/or existing medical conditions (e.g., elevated LDL cholesterol levels, other lipid disorders, insulin-dependent diabetes, insulin resistance, or metabolic syndrome). Other changeable risk factors warranting patient education include strategies to encourage patients, especially those who are overweight and with high blood pressure, to safely decrease sodium intake, achieve a normal weight, ensure regular participation in moderate aerobic physical activity three to four times per week, eliminate tobacco use, and adhere to a heart-healthy diet. If triglycerides also are elevated, the patient should be advised to eliminate or reduce alcohol. The 2013 Guideline on Lifestyle Management to Reduce Cardiovascular Risk published by the American College of Cardiology (ACC) and the American Heart Association (AHA) in conjunction with the National Heart, Lung, and Blood Institute (NHLBI) recommends a “Mediterranean”-style diet rather than a low-fat diet. The new guideline emphasizes inclusion of vegetables, whole grains, fruits, low-fat dairy, nuts, legumes, and nontropical vegetable oils (e.g., olive, canola, peanut, sunflower, flaxseed) along with fish and lean poultry. A similar dietary pattern known as the Dietary Approaches to Stop Hypertension (DASH) diet makes additional recommendations for the reduction of dietary sodium. Both dietary styles emphasize a reduction in consumption of red meats, which are high in saturated fats and cholesterol, and other foods containing sugar, saturated fats, trans fats, and sodium.
- Social and Cultural Considerations: Numerous studies point to the prevalence of excess body weight in American children and adolescents. Experts estimate that obesity is present in 25% of the population ages 6 to 11 yr. The medical, social, and emotional consequences of excess body weight are significant. Special attention should be given to instructing the child and caregiver regarding health risks and weight control education.
- Recognize anxiety related to test results, and be supportive of fear of shortened life expectancy. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Educate the patient regarding access to counseling services. Provide contact information, if desired, for the American Heart Association (www.americanheart.org) or the NHLBI (www.nhlbi.nih.gov).
- Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
- Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
- Related tests include antiarrhythmic drugs, apolipoprotein A and B, AST, ANP, blood gases, BNP, calcium (blood and ionized), cholesterol (total, HDL, and LDL), CT cardiac scoring, CRP, CK and isoenzymes, echocardiography, glucose, glycated hemoglobin, Holter monitoring, homocysteine, ketones, LDH and isoenzymes, magnesium, MRI chest, MI scan, myocardial perfusion heart scan, myoglobin, PET heart, potassium, triglycerides, and troponin.
- Refer to the Cardiovascular System table at the end of the book for related tests by body system.