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CD4 + T‐lymphocyte enumeration with a flow‐rate based method in three flow cytometers with different years in service
Author(s) -
Pattanapanyasat Kovit,
Chimma Pattamawan,
Sratongno Panudda,
Lerdwana Surada
Publication year - 2008
Publication title -
cytometry part b: clinical cytometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 61
eISSN - 1552-4957
pISSN - 1552-4949
DOI - 10.1002/cyto.b.20425
Subject(s) - flow cytometry , volumetric flow rate , flow (mathematics) , biomedical engineering , statistics , medicine , mathematics , immunology , physics , mechanics , geometry
Background CD4 + T‐lymphocyte count remains the most important surrogate marker for management of HIV patients in resource‐poor countries. The standard single‐platform (SP) bead‐based flow cytometric method for CD4 + testing is expensive; more affordable methods are needed. We evaluated the SP flow‐rate‐based calibration method for determining CD4 + counts, using three flow cytometers of varying ages. Methods CD4 + counts from 103 HIV‐1 infected Thai patients were determined using a SP flow‐rate method in flow cytometers with 2, 12, and 16 years of service. Results were compared to the bead‐based method. Correlation and agreement were analyzed using linear regression and Bland‐Altman analysis. Results Counts obtained from the flow‐rate approach in each flow cytometer showed strong correlation with the bead‐based method ( R 2 = 0.97, 0.97, and 0.96 for the 2‐, 12‐, and 16‐year‐old flow cytometers). The mean biases for the flow‐rate approach compared with the bead‐based method were +32.4 cells/μL (limit of agreement (LOA): −83.0 to +147.8 cells/μL), −28.8 cells/μL (LOA: −131.6 to +74.1 cells/μL), and −27.0 cells/μL (LOA: −149.4 to +95.4 cells/μL). Conclusion The flow‐rate approach is reliable for determining CD4 + counts. Results do not vary by age of flow cytometer. This approach provides a cost‐effective alternative for HIV patient monitoring in resource‐poor settings. © 2008 Clinical Cytometry Society