Test Background Enumeration of peripheral blood T-cells (CD3, CD4, CD8), B-cells (CD19) and NK cells (CD56). Other lymphocyte surface markers can also be enumerated. HIV positive patients may have reduced T-helper (CD4) lymphocytes or a reduced T-helper: T-suppressor (CD8) cell ratio, usually in conjunction with an absolute lymphocytopenia. This test is now recommended as an early indicator of the development of AIDS in HIV positive subjects. It is not specific for HIV infection and other viral conditions, non-Hodgkin’s Lymphoma, SLE and sarcoidosis may also be associated with a low count.
Clinical Indications Early indicator of the development of AIDS in HIV positive subjects.
Reference Range Adult ranges (>18 years)
CD3+ T lymphocytes Percentage 55-83
CD3+ T lymphocytes Absolute 700-2100
CD3+/CD4+ T lymphocyte Percentage 28-57
CD3+/CD4+ T lymphocyte Absolute 300-1400
CD3+/CD8+ T lymphocyte Percentage 10-39
CD3+/CD8+ T lymphocyte Absolute 200-900
CD19+ B lymphocyte Percentage 6-19
CD19+ B lymphocyte Absolute 100-500
CD3-/CD16-CD56+ NK cells Percentage 7-31
CD3-/CD16-CD56+ NK cells Absolute 90-600
Absolute Lymphocytes 1000-2800
NB values for children vary according to age
Sample Required EDTA (lavender top) Do not separate or refrigerate Test within 24 hours Please label ‘risk specimen’ if HIV positive
Sample Volume 3 mL
Turnaround Time 3 days
Notes Please discuss with the Immunology laboratory on ext. 10130.