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Updated: Jun 3, 2026
Comprehensive & Cost Effective Laboratory Monitoring of HIV/AIDS: an African Role Model
Published on: October 31, 2010
Absolute lymphocyte count: a cost-effective method of monitoring HIV-infected individuals
1Department of Medicine, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi 110 060, India.
Insights
Absolute lymphocyte count (ALC) can be a cost-effective substitute for CD4 cell count in HIV patients. An ALC threshold of 1520/μL offers higher sensitivity for identifying individuals needing treatment.
Area of Science:
- Immunology
- Infectious Diseases
- Public Health
Background:
- CD4 cell depletion is a key indicator of AIDS progression.
- Accurate CD4 counts are crucial for initiating antiretroviral therapy (ART) and opportunistic infection prophylaxis.
- The World Health Organization (WHO) suggests using absolute lymphocyte count (ALC) as a surrogate for CD4 cell count in resource-limited settings.
Purpose of the Study:
- To evaluate the correlation between CD4 cell count and ALC in HIV-infected individuals.
- To determine the utility of ALC as a cost-effective alternative to CD4 cell count for clinical decision-making.
Main Methods:
- A cross-sectional study analyzing blood samples from HIV-infected patients.
- Simultaneous measurement of CD4 cell counts and ALC from December 2004 to December 2005.
- Statistical analysis to assess the correlation and predictive values between ALC and CD4 cell counts.
Main Results:
- A significant positive correlation (r=0.714) was observed between ALC and CD4 cell count.
- An ALC of ≤1200/μL correctly identified 77.6% of patients with CD4 counts ≤200/μL (true positives).
- The study found an ALC threshold of ≤1520/μL provided higher sensitivity (78%) for predicting CD4 counts ≤200/μL.
Conclusions:
- Absolute lymphocyte count (ALC) demonstrates significant correlation with CD4 cell count in HIV patients.
- An ALC threshold of ≤1520/μL offers improved sensitivity for identifying individuals requiring ART compared to the WHO's ≤1200/μL guideline.
- While cost-effective, using ALC alone may lead to a proportion of patients needing ART being missed.
Aim:
Depletion of CD4 cell count is a hallmark of disease progression in AIDS. CD4 cell count is essential for physicians to decide about the timing of initiation of antiretroviral therapy (ART) and for prophylaxis of opportunistic infections. WHO has recommended that, absolute lymphocyte count (ALC) of ≤1200/μL can substitute CD4 cell count of ≤200/μL in resource-constrained countries throughout the world.
Materials And Methods:
This study was undertaken to know whether there is a correlation between CD4 cell count and ALC in HIV-infected individuals. A single sample of blood was withdrawn for ALC and CD4 cell count. The samples received from December 1, 2004 to December 31, 2005 were analyzed.
Results:
A total of 196 samples were collected from 185 patients. After exclusion, a total of 182 samples were analyzed. Results revealed that male:female ratio was 126:56 and their age ranged from 13 to 67 years. The median ALC was 1747 cells/μL, whereas the CD4 cell count ranged from 5 to 2848. The correlation coefficient between ALC and CD4 cell count was significant (0.714). There were 49 patients with an ALC of ≤1200/μL of whom 77.6% patients had CD4 cell count ≤ 200/μL (true positive) and 22.4% had CD4 cell count > 200/μL (false positive). There were 133 patients with an ALC of >1200/μL of whom 84.2% had CD4 cell count > 200/μL (true negative) and 15.8% had CD4 cell count ≤ 200/μL (false negative). Taking ALC of ≤1200/μL as a predictor of CD4 cell count ≤ 200/μL ,the sensitivity of the test was 64.4% and specificity was 91.1%. The positive predictive value was 77.6%, negative predictive value was 84.2%, and accuracy was 82.4%.
Conclusion:
We found that an ALC of ≤ 1520/μL has higher sensitivity (78%) for a CD4 cell count of ≤ 200/μL. The ALC was found to be significantly cost-effective in our setup but chances of missing out patients requiring ART was 1 in 5 using the WHO guidelines.
