Absolute Lymphocyte Count Calculator
Calculate absolute lymphocyte count from CBC results and assess immune function
Calculate Absolute Lymphocyte Count
Normal range: 4,000-11,000 cells/μL
Normal range: 20-40% of total WBC count
Formula:
ALC = WBC × LYMPH%
Example Calculation
Given: WBC = 8,000 cells/μL, Lymphocytes = 25%
Calculation: ALC = 8,000 × 0.25 = 2,000 cells/μL = 2.0 × 10³ cells/μL
Interpretation: Normal range (adequate immune function)
Types of Lymphocytes
T Cells (T Lymphocytes)
Function: Cell-mediated adaptive immunity
CD4+ T cells (Helper T cells): Coordinate immune response, targeted by HIV
CD8+ T cells (Cytotoxic T cells): Destroy infected or abnormal cells
Clinical Note: CD4+ count < 200 cells/μL defines AIDS
B Cells (B Lymphocytes)
Function: Humoral immunity - antibody production
Plasma cells: Differentiated B cells that secrete antibodies
Memory B cells: Provide long-term immunity
Clinical Note: Elevated in chronic infections, autoimmune diseases
NK Cells (Natural Killer Cells)
Function: Cytotoxic innate immunity
Target: Virus-infected cells, tumor cells
Mechanism: Direct cell lysis without prior sensitization
Clinical Note: First line of defense against malignancies
Clinical Conditions Associated with Lymphocyte Changes
Lymphopenia Causes
Infections:
- • HIV/AIDS
- • Severe sepsis
- • Tuberculosis
- • Hepatitis
Medications:
- • Corticosteroids
- • Chemotherapy
- • Immunosuppressants
- • Radiation therapy
Autoimmune:
- • Systemic lupus erythematosus
- • Rheumatoid arthritis
- • Sjögren's syndrome
Other Causes:
- • Malnutrition
- • Chronic kidney disease
- • Aplastic anemia
- • Sarcoidosis
Lymphocytosis Causes
Viral Infections:
- • Epstein-Barr virus (EBV)
- • Cytomegalovirus (CMV)
- • Influenza
- • Hepatitis
Malignancies:
- • Chronic lymphocytic leukemia
- • Acute lymphoblastic leukemia
- • Lymphomas
- • Multiple myeloma
Other Causes:
- • Hyperthyroidism
- • Addison's disease
- • Smoking
- • Stress response
Chronic Conditions:
- • Pertussis
- • Toxoplasmosis
- • Brucellosis
- • Recovery from infections
Reference Ranges
Normal Range
1.5 - 3.0 × 10³ cells/μL
20-40% of total WBC
Lymphopenia
< 1.5 × 10³ cells/μL
Increased infection risk
Severe Lymphopenia
< 0.95 × 10³ cells/μL
HIV risk marker
Lymphocytosis
> 3.0 × 10³ cells/μL
Often viral infections
HIV/AIDS Risk Assessment
High Risk
ALC < 0.95 × 10³ cells/μL
CD4+ < 200 cells/μL very likely
Low Risk
ALC > 1.7 × 10³ cells/μL
CD4+ < 200 cells/μL unlikely
AIDS Definition
CD4+ count < 200 cells/μL or opportunistic infections
About Lymphocytes
Function
Key components of adaptive immunity, providing specific defense against pathogens
Location
Circulate in blood and lymphatic system, concentrate in lymph nodes and spleen
Lifespan
Variable: days to decades (memory cells can persist for life)
Clinical Significance
Immune Function Assessment
- • Primary immunodeficiency screening
- • HIV/AIDS monitoring
- • Post-transplant surveillance
Infection Risk Stratification
- • Pre-surgical assessment
- • Chemotherapy monitoring
- • Opportunistic infection risk
Disease Monitoring
- • Autoimmune disease activity
- • Hematologic malignancy screening
- • Treatment response monitoring
Understanding Absolute Lymphocyte Count
What is ALC?
The Absolute Lymphocyte Count (ALC) measures the actual number of lymphocytes per unit volume of blood. Unlike the lymphocyte percentage, which can be misleading when total WBC count is abnormal, the ALC provides the true lymphocyte concentration.
Clinical Applications
- •HIV/AIDS monitoring and CD4+ count prediction
- •Immunodeficiency screening and assessment
- •Infection risk stratification in hospitalized patients
- •Monitoring response to immunosuppressive therapy
Calculation Method
Formula
ALC = WBC Count × Lymphocyte %
Required Values
- • Total WBC count (from CBC)
- • Lymphocyte percentage (from differential)
Result Units
Usually expressed as × 10³ cells/μL
HIV Correlation
Research Finding: ALC < 0.95 × 10³ cells/μL strongly predicts CD4+ count < 200 cells/μL, making it a useful screening tool in resource-limited settings.