White blood cells (WBC)
Absolute lymphocyte count

The absolute lymphocyte count calculator uses white blood cell count and lymphocyte percentage to estimate the total number of these immune system cells in one's blood. It also interprets the result in terms of HIV-induced immunodeficiency.

After you find the total lymphocyte count, you might be interested in our other calculators regarding the white blood cells:

What are lymphocytes?

Lymphocytes are a vital part of the immune system - they are the largest group among the many kinds of white blood cells (WBC). Their name corresponds to the fact that they are the main solid compound of lymph. This word is derived from the name of the ancient Roman deity of fresh water, Lympha.

Lymphocytes can be recognized by their large nucleus. All of them cover the defensive function of the organism, but have different roles and vary greatly. The whole group includes:

  • NK - natural killer cells (which function in cell-mediated, cytotoxic innate immunity);
  • T cells - for cell-mediated, cytotoxic adaptive immunity. Some of them, called CD4+, are attacked by the HIV virus, so their decrease can signal an AIDS infection;
  • B cells - for humoral, antibody-driven adaptive immunity.

What is a normal total lymphocyte count?

The total lymphocyte count of a healthy person should range between 1.5 and 3 ×10³ cells/μL. This number elevates in states of viral infections and, very rarely, can be a sign of leukemia. A low total lymphocyte count can be associated with increased rates of infection after surgery or trauma. A progressive reduction of CD4+ T-cells (especially below 200 cells/μL) indicates immunodeficiency that can be linked to AIDS. According to the article Absolute lymphocyte count in the emergency department predicts a low CD4 count in admitted HIV-positive patients:

A CD4 count of < 200 cells/μL is very likely if the ALC (absolute lymphocyte count) is below 0.95 ×10³ cells/μL and less likely if the ALC is over 1.700 ×10³ cells/μL.

That means that the absolute lymphocyte count can be used as a rough, but easily obtainable marker of HIV-induced immunodeficiency.

What formula does the absolute lymphocyte count calculator use?

To estimate the total lymphocyte count (ALC), you first need to do a complete blood count (CBC). The values of white blood cell (WBC) count and lymphocyte percentage (LYMPH%) are going to be used in this equation:


The calculated absolute lymphocyte count is expressed in thousands of cells per microlitre (10³ cells/μL).

Małgorzata Koperska, MD