Test Id : TCD4
CD4 Count for Immune Monitoring, Blood
Useful For
Suggests clinical disorders or settings where the test may be helpful
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
This assay should not be used for diagnosing T-lymphocytic malignancies or evaluation of T-cell lymphocytosis of unknown etiology.
Method Name
A short description of the method used to perform the test
Flow Cytometry
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
CD4 Count
CD8 Count, Flow Cytometry
Helper Suppressor Ratio
Immune Competence
Immune Status-Flow Cytometry
Immunodeficiency Panel-Flow Cytometry
Quantitative CD4 and CD8
T Cell
T Cells
T Lymphocyte Surface Markers
T-Cell Surface Markers
T-Cells
T-Helper/T-Suppressor-Flow Cytometry
T4/T8 Helper Suppressor Ratio
AIDS (Acquired Immune Deficiency Syndrome)
Specimen Type
Describes the specimen type validated for testing
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
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Container/Tube: Lavender top (EDTA)
Specimen Volume: 3 mL
Collection Instructions: Send whole blood 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
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
1 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Ambient | 72 hours | PURPLE OR PINK TOP/EDTA |
Useful For
Suggests clinical disorders or settings where the test may be helpful
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
This assay should not be used for diagnosing T-lymphocytic malignancies or evaluation of T-cell lymphocytosis of unknown etiology.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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 US Public Health Service has recommended that all patients who are HIV-positive 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 of all ages with primary cellular immunodeficiencies, 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.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
The appropriate age-related reference values will be provided on the report.
Interpretation
Provides information to assist in interpretation of the test results
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)
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
T-cell counts should be appropriately interpreted in context of the clinical presentation and other immunological parameters and relevant laboratory test results.
For serial monitoring of T-cell numbers, it is recommended that the patient be evaluated at the same time of the day to account for diurnal variation.
For follow-up of infants identified by newborn screening for severe combined immunodeficiency (SCID) and severe T-cell lymphopenia, SCID should be considered as a potential diagnosis in infants with fewer than 300 autologous CD3 T cells/mcL. Infants with 300 to 1500 autologous CD3 T cells/mcL may have leaky SCID, Omenn syndrome, or variant SCID, depending on other clinical and molecular features.
In infants identified by newborn screening for SCID, T-cell lymphopenia is defined as having up to 1500 autologous CD3T cells/mcL.
This assay should not be used for diagnosing T-lymphocytic malignancies or evaluation of T-cell lymphocytosis of unknown etiology, though the latter may be identified through this assay in a screening assessment. In such cases, LCMS / Leukemia/Lymphoma Immunophenotyping, Flow Cytometry, Varies will be recommended, which includes a hematopathology review.
Also, when diagnostically assessing lymphocyte subsets (quantitatively) in any of the above clinical contexts, it may be more useful to order the T-cell, B-cell, and natural killer (NK)-cell quantitation assay rather than the T-cell subset quantitation alone, as it excludes B-and NK-cell counts.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
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;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;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;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;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. [published correction appears in Clin Infect Dis. 2022 May 30;74(10):1893-1898. doi: 10.1093/cid/ciab801] [published correction appears in Clin Infect Dis. 2022 Nov 30;75(11):2052. doi: 10.1093/cid/ciac474]. Clin Infect Dis. 2021;73(11):e3572-e3605
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
Method Description
Describes how the test is performed and provides a method-specific reference
The T cell surface marker assay uses monoclonal antibodies to identify the various membrane antigens, and flow cytometry to enumerate the number of cells expressing these differentiation antigens. CD14 is used to exclude monocytes, thereby improving accuracy and enhancing the purity of the lymphocyte population. The results are reported as the percent of lymphocytes that are total T cells (CD3+), CD3+CD4+ T cells, and CD3+CD8+ T cells, along with the absolute number of each cell type per microliter of blood. The assay is a 5-color, no-wash procedure and the absolute counts are calculated from internal bead standards. The total CD45+ lymphocyte count (reported as thousand cells per microliter) and the CD4:CD8 ratio are also reported.(Hoffman RA, Kung PC, Hansen WP, Goldstein G. Simple and rapid measurement of human T lymphocytes and their subclasses in peripheral blood. Proc Natl Acad Sci USA. 1980;77(8):4914-4917; Mandy FF, Nicholson JK, McDougal JS. CDC. Guidelines for performing single-platform absolute CD4+ T-cell determinations with CD45 gating for persons infected with human immunodeficiency virus. Centers for Disease Control and Prevention. MMWR Recomm Rep. 2003;52[RR-2]:1-13)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Sunday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
86359-T cells, total count
86360-Absolute CD4/CD8 count with ratio
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| TCD4 | CD4 T-Cell Count | 80721-4 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| 3322 | CD3 (T Cells) | 8122-4 |
| 3319 | % CD4 (T Cells) | 8123-2 |
| 3325 | CD4 (T Cells) | 24467-3 |
| 3326 | CD8 (T Cells) | 14135-8 |
| 3327 | 4/8 Ratio | 54218-3 |
| 3321 | CD45 Total Lymph Count | 27071-0 |
| 3316 | % CD3 (T Cells) | 8124-0 |
| 3320 | % CD8 (T Cells) | 8101-8 |
| CMTTC | Comment | 69052-9 |