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HelpEpic Test Code LAB3758 CD4 Count for Monitoring, New York, Blood
Additional Codes
MML Code: CD4NY
NY State Approved
YesPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
CD4 T-Cell Count, New YorkMethod Name
Flow Cytometry
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Ambient | 72 hours | PURPLE OR PINK TOP/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 and time of collection are required.
Specimen Required
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.
Due to limited specimen stability, and the need to transport to our reference laboratory (Mayo), these tests MUST be drawn and received as outlined below.
Monday through Friday during non-holidays.
- MIB prior to 3:00 pm.
- Fox Prior to 2:00 pm
- OCH prior to 12:30 pm
- HLS prior to 2:00 pm
- LFH prior to 11:00
- FTT prior to 11:00
- These tests cannot be drawn the day before or on the following holidays: New Years, Memorial Day, Independence Day, Labor Day, Thanksgiving, and Christmas.
Blood Tube Draw Volume
Min 50% draw volume
- 50% of the tube fill volume is required for proper blood to additive ratio.
Specimen Type
Whole Blood EDTASpecimen Minimum Volume
1 mL
Reference Values
The appropriate age-related reference values will be provided on the report.
Report Available
3 to 4 daysDay(s) Performed
Monday through Sunday
CPT Code Information
86359-T cells, total count
86360-Absolute CD4/CD8 count with ratio
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
Useful For
Only orderable by New York clients
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.
Disease States
- HIV infection
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 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 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 a CD4 count 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
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 autologous CD3 T cells at or below 1500 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.