ABSTRACT
<p><b>OBJECTIVE</b>This study is aimed at evaluating the utility of the portable CD4 analyzers (PIMA).</p><p><b>METHODS</b>The paired finger prick blood (25 µl) and 5 ml venous blood samples were collected from 196 HIV infected patients, who came to Yunnan CDC voluntary counseling and testing (VCT) clinic for CD4 test services, from May to August, 2012. The absolute CD4 cell counts were measured by PIMA (using venous and finger-prick blood) and by Calibur (using venous blood) as the reference. The PIMA and Calibur CD4 results were compared using the Wilcoxon matched-pairs test, and the Spearman's rank correlation coefficients were estimated. The Bland-Altman plots were used to assess the consistency of the two methods.</p><p><b>RESULTS</b>The median absolute CD4 counts of 196 venous blood samples obtained by PIMA and by Calibur were 268 (range:169-403) cells/µl and 302 (range:181-474) cells/µl respectively, which showed significant difference (Z = -7.31, P < 0.01). The median absolute CD4 counts measured by PIMA and by Calibur (using 188 finger-prick and venous blood samples respectively) were 271 (range: 165-450) cells/µl and 304 (range:188-476) cells/µl, which also showed significant difference (Z = -7.60, P < 0.01). The CD4 counts obtained by PIMA CD4 analyzer (using venous and finger-prick blood) showed strong positive correlation with the CD4 counts obtained by the reference method (using venous blood), and the r values were 0.94 and 0.92 respectively (P < 0.01) . The mean biases (limit of agreement) were -38.7 (-210.9-133.5)cells/µl and -45.4 (-221.8-131.0) cells/µl, respectively.Using 350 CD4 counts as the threshold for ART treatment initiation, the sensitivity and specificity of PIMA were 99.1% and 79.3% for venous blood samples, and 97.2%and 78.5% for finger-prick blood samples, respectively.</p><p><b>CONCLUSION</b>The CD4 counts obtained by PIMA are lower than that obtained by Calibur, while the sensitivity is high.</p>
Subject(s)
Adolescent , Adult , Aged , Child , Female , Humans , Male , Middle Aged , Young Adult , CD4 Lymphocyte Count , Methods , Flow Cytometry , Methods , HIV Infections , Blood , Sensitivity and SpecificityABSTRACT
<p><b>OBJECTIVE</b>To timely identify the HIV-1 infection in window-period and to estimate the HIV-1 incidence among people who came for voluntary counseling and testing (VCT) service as well as men who have sex with men (MSM), respectively.</p><p><b>METHODS</b>HIV antibody negative samples that were determined by screening tests between January and October 2012, were collected and tested with pooling HIV-1 RNA testing technique (2-staged pooling by 50:1, 10:1). Positive cases were followed-up for HIV antibody testing while HIV incidence was calculated under Ron Brookmeyer' s method, among VCT and MSM populations.</p><p><b>RESULTS</b>Among 1400 HIV antibody negative samples of VCT, two showed HIV-1 RNA positive during the antibody window period with the HIV-1 incidence as 1.87% per year (95% CI: 1.23%-2.65% ). Among 500 HIV antibody negative samples from MSM population, two showed HIV-1 RNA positive in the antibody window period, with HIV-1 incidence as 5.31% per year (95% CI: 3.52%-7.45% ).</p><p><b>CONCLUSION</b>Pooling HIV-1 RNA testing seemed a powerful tool for HIV antibody testing in the window-period. Measures should be taken to strengthen the HIV diagnostic programs among MSM and other high risk groups,during the HIV antibody window-period. More frequent detection approach as pooling HIV-1 RNA testing might be a good choice.</p>