CD4/CD8 Enumeration

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CD4/CD8 Enumeration

Synonym/acronym: T-cell profile.

Common use

To monitor HIV disease progression and the effectiveness of retroviral therapy.

Specimen

Whole blood (1 mL) collected in a green-top (heparin) tube.

Normal findings

(Method: Flow cytometry)
Mature T cells (CD3)Helper T cells (CD4)Suppressor T cells(CD8)
AgeAbsolute (cells/microL)%Absolute (cells/microL)%Absolute(cells/microL)%
0–3 mo2,500–5,50053–841,600–4,00035–64560–1,70012–28
3–6 mo2,500–5,60051–771,800–4,00035–56590–1,60012–23
6–12 mo1,900–5,90049–761,400–4,30031–56500–1,70012–24
12–24 mo2,100–6,20053–751,300–3,40032–51620–2,00014–30
2–56 yr1,400–3,70056–75700–2,20028–47490–1,30016–30
6–12 yr1,200–2,60060–76650–1,50031–47370–110018–35
12–18 yr1,000–2,20056–84530–1,30031–52330–92018–35
Adult527–2,84649–81332–1,64228–51170–81112–38
Pediatric values adapted with permission by Elsevier from Shearer, W., et. al. (November, 2003). Lymphocyte subsets in healthy children from birth through 18 years of age: The pediatric AIDS clinical trials group P1009 study. Journal of Allergy and Clinical Immunology. 112(5): 973–980.

Description

Enumeration of lymphocytes, identification of cell lineage, and identification of cellular stage of development are used to diagnose and classify malignant myeloproliferative diseases and to plan treatment. T-cell enumeration is also useful in the evaluation and management of immunodeficiency and autoimmune disease. The CD4 count is a reflection of immune status. It is used to make decisions regarding initiation of antiretroviral therapy (ART) and is also an excellent predictor of imminent opportunistic infection. A sufficient response for patients receiving ART is defined as an increase of 50 to 150 (cells/microL) per year with rapid response during the first 3 mo of treatment followed by an annual increase of 50 to 100 (cells/microL) until stabilization is achieved. HIV viral load is another important test used to establish a baseline for viral activity when a person is first diagnosed with HIV and then afterward to monitor response to ART. Viral load testing, also called plasma HIV RNA, is performed on plasma from a whole blood sample. The viral load demonstrates how actively the virus is reproducing and helps determine whether treatment is necessary. Optimal viral load is considered to be less than 20 to 75 copies/mL or below the level of detection, but the actual level of detection varies somewhat by test method. Methods commonly used to perform viral load testing include branched DNA (bDNA) or reverse transcriptase polymerase chain reaction (RT-PCR). Results are not interchangeable from method to method. Therefore, it is important to use the same viral load method for serial testing. Public health guidelines recommend CD4 counts and viral load testing upon initiation of care for HIV; 3 to 4 mo before commencement of ART; every 3 to 4 mo, but no later than 6 mo, thereafter; and if treatment failure is suspected or otherwise when clinically indicated. Additionally, viral load testing should be requested 2 to 4 wk, but no later than 8 wk, after initiation of ART to verify success of therapy. In clinically stable patients, CD4 testing may be recommended every 6 to 12 mo rather than every 3 to 6 mo. Guidelines also state that treatment of asymptomatic patients should begin when CD4 count is less than 350 cells/microL; treatment is recommended when the patient is symptomatic regardless of test results or when the patient is asymptomatic and CD4 count is between 350 and 500 cells/microL. Failure to respond to therapy is defined as a viral load greater than 200 copies/mL. Increased viral load may be indicative of viral mutations, drug resistance, or noncompliance to the therapeutic regimen. Testing for drug resistance is recommended if viral load is greater than 1,000 copies/mL.

This procedure is contraindicated for

    N/A

Indications

  • Assist in the diagnosis of AIDS and plan treatment
  • Evaluate malignant myeloproliferative diseases and plan treatment
  • Evaluate thymus-dependent or cellular immunocompetence

Potential diagnosis

Increased in

  • Malignant myeloproliferative diseases (e.g., acute and chronic lymphocytic leukemia, lymphoma)

Decreased in

    AIDS Aplastic anemia Hodgkin’s disease

Critical findings

    N/A

Interfering factors

  • Drugs that may increase T-cell count include interferon-γ.
  • Drugs that may decrease T-cell count include chlorpromazine and prednisone.
  • Specimens should be stored at room temperature.
  • Recent radioactive scans or radiation can decrease T-cell counts.
  • Values may be abnormal in patients with severe recurrent illness or after recent surgery requiring general anesthesia.

Nursing Implications and Procedure

Potential nursing problems

ProblemSigns & SymptomsInterventions
Gas exchange (Related to insufficient oxygen supply secondary to pulmonary infiltrates; sepsis; hyperventilation)Decreased activity tolerance; increased shortness of breath with activity; weakness; orthopnea; cyanosis; cough; increased heart rate; weight gain; edema in the lower extremities; weakness; increased respiratory rate; use of respiratory accessory muscles Auscultate and trend breath sounds; use pulse oximetry to monitor oxygenation; administer oxygen as ordered; collaborate with physician to consider intubation and/or mechanical ventilation; place the head of the bed in high Fowler’s position; administer diuretics, vasodilators as ordered; monitor arterial blood gas (ABG) results; monitor color and character of sputum; encourage periods of rest; administer prescribed medications for Pneumocystis jiroveci (Trimethoprim/sulfamethoxazole [TMP-SMX], pentamidine), administer prescribed steroids
Infection (Related to altered immune system; malnutrition; chemotherapy)Symptoms of infection (temperature, increased heart rate, increased blood pressure, shaking, chills, mottled skin, lethargy, fatigue, swelling, edema, pain, localized pressure, diaphoresis, night sweats, confusion, vomiting, nausea, headache); night sweats; persistent cough; adventitious breath sounds (crackles, course, diminished) Decrease exposure to environment by placing the patient in a private room; monitor and trend vital signs; monitor and trend laboratory values that would indicate an infection (white blood cells [WBC], C-reactive protein [CRP]); promote good hygiene; assist with hygiene as needed; administer prescribed antibiotics, antipyretics; provide cooling measures; administer prescribed IV fluids; monitor vital signs and trend temperatures; encourage oral fluids; adhere to standard or universal precautions; provide isolation as appropriate; obtain cultures as ordered; provide lightweight clothing and bedding; assess for night sweats; assess for cough and sputum color if productive, check for blood in sputum; use isolation as appropriate (TB); encourage use of incentive spirometer
Nutrition (Related to fatigue; malabsorption; nausea [medication side effect]; effects of chemotherapy) Unintended weight loss; current weight 20% below ideal weight; skin tone loss and pale dry skin; dry mucous membranes; documented inadequate caloric intake; subcutaneous tissue loss; hair pulls out easily; paresthesis; muscle wasting Obtain accurate daily weight at the same time each day with the same scale; obtain an accurate nutritional history; assess attitude toward eating; promote a dietary consult to evaluate current eating habits and best method of nutritional supplementation; develop short-term and long-term eating strategies; monitor nutritional laboratory values such as albumin, transferrin, red blood cells [RBC], WBC, and serum electrolytes; discourage caffeinated and carbonated beverages; assess swallowing ability; encourage cultural home foods; provide a pleasant environment for eating; alter food seasoning to enhance flavor; provide parenteral or enteral nutrition as prescribed, if used check gastric residual every 4 hr; encourage good oral hygiene; provide frequent small meals; administer prescribed antiemetics
Tissue integrity (Related to insufficient nutrition; vomiting and diarrhea secondary to medication side effects, chemotherapy; altered mobility) Area on the skin that is warm or tender to touch; skin that turns red, purple, or black; localized pain; swelling of affected areaConduct baseline skin assessment of frequent re-assessment using a standardized scale (Braden); monitor and note the presence of herpes lesions; encourage the use of hypoallergenic soap and lanolin products, pat rather than rub skin dry; avoid bed wrinkles; ensure sheets are soft and gentle on skin; encourage adequate nutrition; administer prescribed vitamin supplements; encourage and assist range of motion; assess the characteristics of a wound (color, size, length, width, depth, drainage, and odor); monitor for fever; identify the cause of the tissue damage

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 diagnosing disease and monitoring the effectiveness of disease therapy.
  • 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 hematopoietic and immune systems and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Note any recent procedures that can interfere with test results.
  • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
  • 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.
  • 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 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.
  • Nutritional Considerations: As appropriate, stress the importance of good nutrition and suggest that the patient meet with a nutritional specialist. Stress the importance of following the care plan for medications and follow-up visits. Inform the patient that subsequent requests for follow-up blood work at regular intervals should be anticipated.
  • Recognize anxiety related to test results, and be supportive of impaired activity related to perceived loss of independence and 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 as to the risk of infection related to immunosuppressed inflammatory response and fatigue related to decreased energy production. Educate the patient regarding access to counseling services.
  • 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.
  • Patient Education

    • Counsel the patient, as appropriate, regarding risk of transmission and proper prophylaxis, and reinforce the importance of strict adherence to the treatment regimen, including consultation with a pharmacist.
    • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
    • Provide contact information, if desired, for the Centers for Disease Control and Prevention (www.cdc.gov).
    • Answer any questions or address any concerns voiced by the patient or family.
  • Expected Patient Outcomes

    • Knowledge
    • States the importance of reporting cough and shortness of breath to ensure early intervention of opportunistic hosts
    • States steps that can be taken in the home environment to decease infection risk
    • Skills
    • Correctly describes the process for the collection of a sputum specimen
    • Demonstrates proficient use of the incentive spirometer
    • Attitude
    • Takes proactive measures to improve overall health by complying with recommended therapeutic plan
    • Complies with the request to refrain from scratching, which causes tissue damage

Related Monographs

  • Related tests include biopsy bone marrow, bronchoscopy, CBC, CBC platelet count, CBC WBC count and differential, culture and smear mycobacteria, culture viral, cytology sputum, gallium scan, HIV-1/HIV-2 antibodies, laparoscopy abdominal, LAP, lymphangiogram, MRI musculoskeletal, mediastinoscopy, and β2-microglobulin.
  • Refer to the Hematopoietic and Immune systems tables at the end of the book for related tests by body system.
References in periodicals archive ?
Approximately three out of four patients re-treated in the second year exhibited a change in their myelin-reactive T-cell profile, which was the basis for producing their individualized T cell vaccine," said David McWilliams, president and chief executive officer of Opexa.

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