section name header

Introduction ⬇

Cholesterol (C) testing evaluates the risk for arthrosclerosis, myocardial occlusion, and coronary arterial occlusion. Cholesterol relates to CAD and is an important screening test for heart disease. It is part of the lipid profile to measure “bad” cholesterol (LDL-C), “good” cholesterol (HDL-C), total cholesterol (LDL-C plus HDL-C), and triglyceride levels.

Elevated cholesterol levels are a major component in the hereditary hyperlipoproteinemias. Cholesterol determinations are also frequently a part of thyroid function, liver function, kidney function, and diabetes studies. It is also used to monitor effectiveness of diet, medications, lifestyle changes (e.g., exercise), and stress management.

Normal Findings ⬆ ⬇

Normal values vary with age, diet, gender, and geographic or cultural region.

Adults, fasting:

Children and adolescents (12–17 years):

Procedure ⬆ ⬇

  1. Obtain a 5-mL venous blood sample (red-topped tube). Fasting is required. Serum is needed.

  2. Observe standard precautions. Label the specimen with the patient’s name, date and time of collection, and test(s) ordered. Place the specimen in a biohazard bag.

Clinical Implications ⬆ ⬇

  1. Total blood cholesterol levels are the basis for classifying CAD risk.

    1. Levels >240 mg/dL or >6.20 mmol/L are considered high and should include follow-up lipoprotein analysis. Borderline high levels (200–239 mg/dL or 5.18–6.19 mmol/L) in the presence of CAD or two other CAD risk factors should also include lipoprotein analysis/profiles.

    2. CAD risk factors include male gender, family history, premature CAD (MI or sudden death before age 55 years in a parent or sibling), smoking (>10 cigarettes per day), hypertension, low HDL-C levels (<35 mg/dL or <0.91 mmol/L confirmed by repeat measurement), diabetes, history of definite cerebrovascular or occlusive peripheral vascular disease, and severe obesity (body mass index >40 kg/m2).

    3. In public screening programs, all patients with cholesterol levels >200 mg/dL or >5.18 mmol/L should be referred to their healthcare providers for further evaluation. Before initiating any therapy, the level should be retested.

  2. Elevated cholesterol levels (hypercholesterolemia) occur in the following conditions:

    1. Type II familial hypercholesterolemia

    2. Hyperlipoproteinemia types I, IV, and V

    3. Cholestasis

    4. Hepatocellular disease, biliary cirrhosis

    5. Nephrotic syndrome, glomerulonephritis

    6. CKD

    7. Pancreatic and prostatic malignant neoplasms

    8. Hypothyroidism

    9. Poorly controlled diabetes

    10. Alcoholism

    11. Glycogen storage disease (von Gierke disease)

    12. Werner syndrome (premature aging; affects 1 in 200,000 persons in the United States)

    13. Diet high in cholesterol and fats (“dietary affluence”)

    14. Obesity

  3. Decreased cholesterol levels (hypocholesterolemia) occur in the following conditions:

    1. Hypo-α-lipoproteinemia

    2. Severe hepatocellular disease

    3. Myeloproliferative diseases

    4. Hyperthyroidism

    5. Malabsorption syndrome, malnutrition

    6. Megaloblastic or sideroblastic anemia (chronic anemias)

    7. Severe burns, inflammation

    8. Conditions of acute illness, infection

    9. COPD

    10. Intellectual disability

Interventions ⬆ ⬇

Pretest Patient Care

  1. Explain test purpose and procedure. An overnight fast before testing is recommended, although nonfasting specimens may be taken. Pretest, a normal diet should be consumed for 7 days. The patient should abstain from alcohol for 48 hours before testing. Prolonged fasting with ketosis increases values.

  2. Document drugs the patient is taking.

  3. Encourage the patient to relax.

  4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Review test results; report and record findings. Modify the nursing care plan as needed. Cholesterol levels are influenced by heredity, diet, body weight, and physical activity. Some lifestyle changes may be necessary to reduce elevated levels (Chart 6.2).

  2. Cholesterol levels >200 mg/dL (or >5.18 mmol/L) should be retested and the results averaged. If the two results differ by >10%, a third test should be done.

  3. Once hyperlipidemia has been established, the diet should be lower in animal fats and should replace saturated fats with polyunsaturated fats. Fruits, vegetables (especially greens), and whole grain products should be increased. Patients with diabetes, as well as others, should seek counsel from a dietitian regarding diet management if necessary. Therapy for hyperlipidemia should always begin with diet modification.

  4. The American Heart Association has excellent resources for providing diet and lifestyle management information.

  5. At least 6 months of dietary therapy should be tried before initiating cholesterol-reducing drug therapy.

  6. Perform a comprehensive lipoprotein analysis if cholesterol levels are not lowered within 6 months after start of therapy.

Clinical Alert

  1. Cholesterol measurement should not be done immediately after MI. A 3-months wait is suggested.

  2. Cholesterol >300 mg/dL or >7.8 mmol/L: There is a strong relationship to CAD, but only a fraction of those with CAD have increased cholesterol.

Interfering Factors ⬆

  1. Pregnancy increases cholesterol levels.

  2. Certain drugs increase cholesterol levels (oral contraceptives, epinephrine, phenothiazines, vitamins A and D, phenytoin, ACTH, anabolic steroids, β-adrenergic blocking agents, sulfonamides, and thiazide diuretic agents).

  3. Certain drugs decrease cholesterol levels (thyroxine, estrogens, androgens, aspirin, antibiotic drugs [tetracycline and neomycin], nicotinic acid, heparin, colchicine, monoamine oxidase inhibitors, allopurinol, and bile salts).

  4. Seasonal variations in cholesterol levels have been observed; levels are higher in fall and winter and lower in spring and summer.

  5. Positional variations occur; levels are lower when sitting versus standing and lower when recumbent versus sitting.

  6. Plasma (EDTA) values are 10% lower than serum.