Antibodies, Antineutrophilic Cytoplasmic

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Antibodies, Antineutrophilic Cytoplasmic

Synonym/acronym: Cytoplasmic antineutrophil cytoplasmic antibody (c-ANCA), perinuclear antineutrophil cytoplasmic antibody (p-ANCA).

Common use

To assist in diagnosing and monitoring the effectiveness of therapeutic interventions for Wegener’s syndrome.

Specimen

Serum (1 mL) collected in a red-top tube.

Normal findings

(Method: Indirect immunofluorescence) Negative.

Description

Antineutrophil cytoplasmic autoantibodies (ANCA) are associated with vasculitis and glomerulonephritis. There are two types of cytoplasmic neutrophil antibodies, identified by their cellular staining characteristics. c-ANCA (cytoplasmic) is specific for proteinase 3 in neutrophils and monocytes and is found in the sera of patients with Wegener’s granulomatosis (WG). Wegener’s syndrome includes granulomatous inflammation of the upper and lower respiratory tract and vasculitis. Systemic necrotizing vasculitis is an inflammation of the blood vessels. p-ANCA (perinuclear) is specific for myeloperoxidase, elastase, and lactoferrin, as well as other enzymes in neutrophils. p-ANCA is present in the sera of patients with pauci-immune necrotizing glomerulonephritis. Diagnosis of WG is difficult because the signs and symptoms are seen in many other diseases. Other than the ANCA blood test, tissue biopsy is the definitive test with presence of granuloma being the positive finding.

This procedure is contraindicated for

    N/A

Indications

  • Assist in the diagnosis of WG and its variants
  • Differential diagnosis of ulcerative colitis
  • Distinguish between biliary cirrhosis and sclerosing cholangitis
  • Distinguish between vasculitic disease and the effects of therapy

Potential diagnosis

Increased in

  • The exact mechanism by which ANCA are developed is unknown. One theory suggests colonization with bacteria capable of expressing microbial superantigens. It is thought that the superantigens may stimulate a strong cellular autoimmune response in genetically susceptible individuals. Another theory suggests the immune system may be stimulated by an accumulation of the antigenic targets of ANCA due to ineffective destruction of old neutrophils or ineffective removal of neutrophil cell fragments containing proteinase, myeloperoxidase, elastase, lactoferrin, or other proteins.

  • c-ANCA
    • WG and its variants
  • p-ANCA
    • Alveolar hemorrhage
    • Angiitis and polyangiitis
    • Autoimmune liver disease
    • Capillaritis
    • Churg-Strauss syndrome
    • Crescentic glomerulonephritis
    • Felty’s syndrome
    • Glomerulonephritis
    • Inflammatory bowel disease
    • Kawasaki’s disease
    • Leukocytoclastic skin vasculitis
    • Microscopic polyarteritis
    • Rheumatoid arthritis
    • Vasculitis

Decreased in

    N/A

Critical findings

    N/A

Interfering factors

    N/A

Nursing Implications and Procedure

Pretest

  • 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 identifying the cause of inflammatory activity.
  • 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 gastrointestinal, genitourinary, hepatobiliary, immune, and musculoskeletal systems; symptoms; and results of previously performed laboratory tests and diagnostic and surgical procedures. The patient should be assessed for signs and symptoms related to renal (related to presence of hematuria or RBC casts), respiratory (related to cough, dyspnea, and/or abnormal chest x-ray showing nodules or infiltrates), cutaneous (related to skin lesions), musculoskeletal (related to painful or arthritic joints), and ear, nose, and throat (related to chronic sinusitis, chronic otitis media, hearing loss, oral ulcers, and/or abnormal nasal dischargeas these sites are most commonly involved in WG.
  • 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.
  • Note that there are no food, fluid, or medication restrictions unless by medical direction.

Intratest

  • Potential complications: N/A
  • 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 the gauze with adhesive bandage.
  • Promptly transport the specimen to the laboratory for processing and analysis.

Post-Test

  • 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.
  • Recognize anxiety related to test results, and be supportive of perceived loss of independence and fear of shortened life expectancy. Discuss the implications of abnormal test results on the patient’s lifestyle. The main goal for treatment of WG is reducing inflammation within the blood vessels in order to prevent further damage to associated sites (kidneys and lungs) and to decrease risk for other complications (eyes, ears, skin, joints). Treatment often includes a combination of immune system suppressants which may include corticosteroids (initially administered in high doses to reduce inflammation and then gradually tapered down), antibiotics (related to infections that arise in the immunosuppressed patient), and cytotoxic drugs (related to immune system suppression). Provide teaching and information regarding the clinical implications of the test results, as appropriate. Educate the patient regarding access to counseling services.
  • 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 Monographs

  • Related tests include ALT, ALKP, antibodies anti-glomerular basement membrane, antibodies AMA/ASMA, antibodies ANA, AST, bilirubin and fractions, biopsy kidney, BUN, CBC, chest x-ray, creatinine, echocardiography, eosinophil count, ESR, MRA, RF, and UA.
  • See the Gastrointestinal, Genitourinary, Hepatobiliary, Immune, and Musculoskeletal systems tables at the end of the book for related tests by body system.