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Assessment of two POC technologies for CD4 count in Morocco
Elmir Elharti
Institut National d'Hygiene Publique
Corresponding Author
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Background : In the era of “test and treat strategy”, CD4 testing remains an important tool for monitoring HIV-infected individuals. Since conventional methods of CD4 count measurement are costly and cumbersome, POC CD4 counting technique are more affordable and practical for countries with limited resources. Before introducing such methods in Morocco, we decided to assess their reliability.
Methods : In this study 92 blood samples from HIV-infected patients, were tested by PIMA and FACSPresto to derive CD4 count. Flow cytometry using FacsCalibur, was used as reference method for CD4 count comparison. Linear regression, Bland-Altman analysis were performed to assess correlation and agreement between these POC methods and the reference method. In addition, sensitivity and specificity, positive predictive value (PPV), negative predictive value (NPV) and misclassification percentage at 350 and 200 CD4 count thresholds; were also determined. Finally, because FACSPresto can also measure hemoglobin (Hb) concentration, 52 samples were used to compare FACSPresto against an automated hematology analyzer.
Results : The coefficient of determination R 2 was 0.93 for both methods. Bland-Altman analysis displayed a mean bias of -32.3 and -8.1 cells/µl for PIMA and FACSPresto, respectively. Moreover, with a threshold of 350 CD4 count, PIMA displayed a sensitivity, specificity, PPV, NPV, were 88.57%, 94.12%, 91.18%, 92.31%; respectively. FACSPresto showed 88.23%, 96.23%,93.75% and 92.73%; respectively. Furthermore, the upward misclassification percentage was 8.57 and 5.88%, for PIMA and FACSPresto, respectively; whereas the downward misclassification percentage was 7.84% and 7.54%; respectively. With 200 cells/µl threshold, PIMA had a sensitivity, specificity, PPV and NPV of 83.33%, 98.53%, 93.75% and 95.71%, respectively. Regarding FACSPresto, sensitivity, specificity, PPV and NPV was 82.35%, 98.57%, 88.57% and 95.83%; respectively. Upward misclassification percentage was 5.56% and 5.88%, for PIMA and FACSPresto, respectively; whereas downward misclassification percentage was 4.41% and 4.29%; respectively. Finally, the hemoglobin measurement evaluation displayed an R 2 of 0.80 and a mean bias of-0.12 with a LOA between -1.75 and 1.51.
Conclusion : When compared to the reference method, PIMA and FACSPresto have shown good performance, for CD4 counting. The introduction of such POC technology will speed up the uptake of patients in the continuum of HIV care, in our country.
Keywords
HIV management, CD4 count, POC, PIMA, FACSPresto, Morocco
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Received 30 Mar, 2020
Reviewer #4 agreed
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Reviewer #5 agreed
On 18 Mar, 2020
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Received 17 Mar, 2020
Reviewer #3 agreed
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Received 26 Feb, 2020
Reviewer #2 agreed
On 17 Feb, 2020
Review #1 received
Received 13 Feb, 2020
Reviewer #1 agreed
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Reviewers invited
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This preprint is under consideration at AIDS Research and Therapy. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research
Assessment of two POC technologies for CD4 count in Morocco
Elmir Elharti
Institut National d'Hygiene Publique
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version 3
Posted 04 Jun, 2020
No community comments so far
Editor assigned
On 30 May, 2020
Submission checks complete
On 29 May, 2020
Editor invited
On 29 May, 2020
No comments provided
Editorial decision: Minor revision
On 15 May, 2020
Editor assigned
On 08 May, 2020
Submission checks complete
On 07 May, 2020
Editor invited
On 07 May, 2020
No comments provided
Editorial decision: Major revision
On 31 Mar, 2020
Review #4 received
Received 30 Mar, 2020
Reviewer #4 agreed
On 18 Mar, 2020
Reviewer #5 agreed
On 18 Mar, 2020
Review #3 received
Received 17 Mar, 2020
Reviewer #3 agreed
On 09 Mar, 2020
Review #2 received
Received 26 Feb, 2020
Reviewer #2 agreed
On 17 Feb, 2020
Review #1 received
Received 13 Feb, 2020
Reviewer #1 agreed
On 31 Jan, 2020
Reviewers invited
Invitations sent on 26 Jan, 2020
Editor assigned
On 18 Jan, 2020
Submission checks complete
On 17 Jan, 2020
Editor invited
On 17 Jan, 2020
First submitted
On 16 Jan, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Infectious Diseases
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background : In the era of “test and treat strategy”, CD4 testing remains an important tool for monitoring HIV-infected individuals. Since conventional methods of CD4 count measurement are costly and cumbersome, POC CD4 counting technique are more affordable and practical for countries with limited resources. Before introducing such methods in Morocco, we decided to assess their reliability.
Methods : In this study 92 blood samples from HIV-infected patients, were tested by PIMA and FACSPresto to derive CD4 count. Flow cytometry using FacsCalibur, was used as reference method for CD4 count comparison. Linear regression, Bland-Altman analysis were performed to assess correlation and agreement between these POC methods and the reference method. In addition, sensitivity and specificity, positive predictive value (PPV), negative predictive value (NPV) and misclassification percentage at 350 and 200 CD4 count thresholds; were also determined. Finally, because FACSPresto can also measure hemoglobin (Hb) concentration, 52 samples were used to compare FACSPresto against an automated hematology analyzer.
Results : The coefficient of determination R 2 was 0.93 for both methods. Bland-Altman analysis displayed a mean bias of -32.3 and -8.1 cells/µl for PIMA and FACSPresto, respectively. Moreover, with a threshold of 350 CD4 count, PIMA displayed a sensitivity, specificity, PPV, NPV, were 88.57%, 94.12%, 91.18%, 92.31%; respectively. FACSPresto showed 88.23%, 96.23%,93.75% and 92.73%; respectively. Furthermore, the upward misclassification percentage was 8.57 and 5.88%, for PIMA and FACSPresto, respectively; whereas the downward misclassification percentage was 7.84% and 7.54%; respectively. With 200 cells/µl threshold, PIMA had a sensitivity, specificity, PPV and NPV of 83.33%, 98.53%, 93.75% and 95.71%, respectively. Regarding FACSPresto, sensitivity, specificity, PPV and NPV was 82.35%, 98.57%, 88.57% and 95.83%; respectively. Upward misclassification percentage was 5.56% and 5.88%, for PIMA and FACSPresto, respectively; whereas downward misclassification percentage was 4.41% and 4.29%; respectively. Finally, the hemoglobin measurement evaluation displayed an R 2 of 0.80 and a mean bias of-0.12 with a LOA between -1.75 and 1.51.
Conclusion : When compared to the reference method, PIMA and FACSPresto have shown good performance, for CD4 counting. The introduction of such POC technology will speed up the uptake of patients in the continuum of HIV care, in our country.
Figure 1