CD3+CD25+ Absolute Unit Converter

CD3+CD25+ Absolute measures the number of T lymphocytes in your blood that display CD25 (the IL-2 receptor alpha chain) on their surface. CD3 confirms that the cell is a T lymphocyte, while CD25 appears when a T cell becomes activated or takes on a regulatory role in the immune system.

This count captures two overlapping populations: recently activated effector T cells responding to an immune challenge and regulatory T cells (Tregs) that help keep immune responses in check. Without additional markers such as FoxP3 and CD127, the test cannot distinguish between these two groups.

The test is reported as an absolute count (cells per microliter of blood) and is typically ordered as part of a lymphocyte subset panel to evaluate overall immune function.

T cells originate from stem cells in the bone marrow and mature in the thymus. CD25 expression occurs when mature T cells become activated in the lymph nodes, spleen, or sites of infection. A subset of regulatory T cells also develops in the thymus with constitutive CD25 expression.