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Test ID TCD4 CD4 Count for Immune Monitoring, Blood

Reporting Name

CD4 T-Cell Count

Useful For

Serial monitoring of CD4 T cell count in patients who are HIV-positive

 

Follow-up and diagnostic evaluation of primary cellular immunodeficiencies, including severe combined immunodeficiency

 

T-cell immune monitoring following immunosuppressive therapy for transplantation, autoimmunity, and other immunological conditions where such treatment is utilized

 

Assessment of T-cell immune reconstitution post hematopoietic cell transplantation

 

Early screening of gross quantitative anomalies in T cells in infection or malignancies

Specimen Type

Whole Blood EDTA


Ordering Guidance


For diagnosing T-lymphocytic malignancies or evaluation of T-cell lymphocytosis of unknown etiology, order LCMS / Leukemia/Lymphoma Immunophenotyping, Flow Cytometry, Varies, which includes a hematopathology review.



Shipping Instructions


It is recommended that specimens arrive within 24 hours of collection. Collect and package specimen as close to shipping time as possible.



Necessary Information


Date of collection is required.



Specimen Required


Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Collection Instructions: Send specimen in original tube. Do not aliquot.

Additional Information: For serial monitoring, it is recommended that specimen collection be performed at the same time of day.


Specimen Minimum Volume

0.2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood EDTA Ambient 72 hours PURPLE OR PINK TOP/EDTA

Reference Values

The appropriate age-related reference values will be provided on the report.

Day(s) Performed

Monday through Sunday

Test Classification

This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

86359-T cells, total count

86360-Absolute CD4/CD8 count with ratio

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TCD4 CD4 T-Cell Count 80721-4

 

Result ID Test Result Name Result LOINC Value
3321 CD45 Total Lymph Count 27071-0
3316 % CD3 (T Cells) 8124-0
3322 CD3 (T Cells) 8122-4
3319 % CD4 (T Cells) 8123-2
3325 CD4 (T Cells) 24467-3
3320 % CD8 (T Cells) 8101-8
3326 CD8 (T Cells) 14135-8
3327 4/8 Ratio 54218-3
CMTTC Comment 69052-9

Clinical Information

Lymphocytes in peripheral blood (circulation) are heterogeneous and can be broadly classified into T cells, B cells, and natural killer cells. There are various subsets of each of these individual populations with specific cell-surface markers and function. This assay provides absolute (cells/mcL) and relative (%) quantitation for total T cells and CD4+ and CD8+ T-cell subsets, in addition to a total lymphocyte count (CD45+). Each of these lymphocyte subpopulations have distinct effector and regulatory functions and are maintained in homeostasis under normal physiological conditions. Each of these lymphocyte subsets can be identified by a combination of 1 or more cell surface markers. The CD3 antigen is a pan-T-cell marker, and T cells can be further divided into 2 broad categories, based on the expression of CD4 or CD8 coreceptors.

 

The absolute counts of lymphocyte subsets are known to be influenced by a variety of biological factors, including hormones, the environment, and temperature. The studies on diurnal (circadian) variation in lymphocyte counts have demonstrated progressive increase in CD4 T-cell count throughout the day, while CD8 T cells increase between 8:30 a.m. and noon with no change between noon and afternoon.(1) Circadian variations in circulating T-cell counts have been shown to be negatively correlated with plasma cortisol concentration.(2-4) In fact, cortisol and catecholamine concentrations control distribution and, therefore, numbers of naive versus effector CD4 and CD8 T cells.(2) It is generally accepted that lower CD4 T-cell counts are seen in the morning compared to the evening(5) and during summer compared to winter.(6)

 

These data, therefore, indicate that timing and consistency in timing of blood collection is critical when serially monitoring patients for lymphocyte subsets.

 

Abnormalities in the number and percent of CD3, CD4, and CD8 T cells have been described in a number of different disease conditions. In patients who are infected with HIV, the CD4 count is measured for AIDS diagnosis and for initiation of antiviral therapy. The progressive loss of CD4 T lymphocytes in patients infected with HIV is associated with increased infections and complications. The Public Health Service has recommended that all HIV-positive patients be tested every 3 to 6 months for the level of CD4 T lymphocytes.

 

Basic T-cell subset quantitation is also very useful in the evaluation of patients with primary cellular immunodeficiencies of all ages, including follow-up for newborn screening for severe combined immunodeficiency and immune monitoring following immunosuppressive therapy for transplantation, autoimmunity, or any other relevant clinical condition where immunomodulatory treatment is used, and the T-cell compartment is specifically affected.

 

It is also helpful as a preliminary screening assay for gross quantitative anomalies in T cells, whether related to malignancies or infection.

Interpretation

HIV treatment guidelines from the US Department of Health and Human Services and the International Antiviral Society USA Panel recommend antiviral treatment in all patients with HIV infection, regardless of CD4 T-cell count.(7,8) Additionally, antibiotic prophylaxis for Pneumocystis jiroveci infection is recommended for patients with CD4 counts below 200 cells/mcL. For other opportunistic infections, see the recommendations from the Centers for Disease Control and Prevention, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America.(9)

Clinical Reference

1. Carmichael KF, Abayomi A: Analysis of diurnal variation of lymphocyte subsets in healthy subjects and its implication in HIV monitoring and treatment. 15th Intl Conference on AIDS, Bangkok, Thailand, 2004, Abstract B11052

2. Dimitrov S, Benedict C, Heutling D, Westermann J, Born J, Lange T: Cortisol and epinephrine control opposing circadian rhythms in T-cell subsets. Blood. 2009 May 21;113(21):5134-5143

3. Dimitrov S, Lange T, Nohroudi K, Born J: Number and function of circulating antigen presenting cells regulated by sleep. Sleep. 2007 Apr;30(4):401-411

4. Kronfol Z, Nair M, Zhang Q, Hill EE, Brown MB: Circadian immune measures in healthy volunteers: relationship to hypothalamic-pituitary-adrenal axis hormones and sympathetic neurotransmitters. Psychosom Med. 1997 Jan-Feb;59(1):42-50

5. Malone JL, Simms TE, Gray GC, Wagner KF, Burge JR, Burke DS: Sources of variability in repeated T-helper lymphocyte counts from HIV 1-infected patients: total lymphocyte count fluctuations and diurnal cycle are important. J Acquir Immune Defic Syndr. 1990;3(2):144-151

6. Paglieroni TG, Holland PV: Circannual variation in lymphocyte subsets, revisited. Transfusion. 1994 Jun;34(6):512-516

7. Panel on Antiretroviral Guidelines for Adults and Adolescents: Guidelines for the use of antiretroviral agents in adults and adolescents living with HIV. Department of Health and Human Services; Updated January 20, 2022. Accessed April 4, 2022. Available at https://clinicalinfo.hiv.gov/sites/default/files/guidelines/documents/guidelines-adult-adolescent-arv.pdf

8. Thompson MA, Horberg MA, Agwu AL, et al: Primary care guidance for persons with human immunodeficiency virus: 2020 update by the HIV Medicine Association of the Infectious Diseases Society of America. Clin Infect Dis. 2021 Dec 6;73(11):e3572-e3605. Erratum in: Clin Infect Dis. 2021 Dec 08

9. Panel on Opportunistic Infections in Adults and Adolescents with HIV. Guidelines for the prevention and treatment of opportunistic infections in adults and adolescents with HIV: recommendations from the Centers for Disease Control and Prevention, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America. Department of Health and Human Services; Updated February 17, 2022. Accessed April 4, 2022. Available at https://clinicalinfo.hiv.gov/en/guidelines

Report Available

Same day/1 to 2 days

Method Name

Flow Cytometry

Mayo Clinic Laboratories | Pediatric Catalog Additional Information:

mcl-newborn