Journal Article > ResearchFull Text
Bull World Health Organ. 25 June 2015; Volume 93 (Issue 9); 623-630.; DOI:10.2471/BLT.14.146480
Fajardo E, Metcalf CJ, Piriou E, Gueguen M, Maman D, et al.
Bull World Health Organ. 25 June 2015; Volume 93 (Issue 9); 623-630.; DOI:10.2471/BLT.14.146480
OBJECTIVE
To estimate the proportion of invalid results generated by a CD4+ T-lymphocyte analyser used by Médecins Sans Frontières (MSF) in field projects and identify factors associated with invalid results.
METHODS
We collated 25,616 CD4+ T-lymphocyte test results from 39 sites in nine countries for the years 2011 to 2013. Information about the setting, user, training, sampling technique and device repair history were obtained by questionnaire. The analyser performs a series of checks to ensure that all steps of the analysis are completed successfully; if not, an invalid result is reported. We calculated the proportion of invalid results by device and by operator. Regression analyses were used to investigate factors associated with invalid results.
FINDINGS
There were 3354 invalid test results (13.1%) across 39 sites, for 58 Alere PimaTM devices and 180 operators. The median proportion of errors per device and operator was 12.7% (interquartile range, IQR: 10.3-19.9) and 12.1% (IQR: 7.1-19.2), respectively. The proportion of invalid results varied widely by country, setting, user and device. Errors were not associated with settings, user experience or the number of users per device. Tests performed on capillary blood samples were significantly less likely to generate errors compared to venous whole blood.
CONCLUSION
The Alere Pima CD4+ analyser generated a high proportion of invalid test results, across different countries, settings and users. Most error codes could be attributed to the operator, but the exact causes proved difficult to identify. Invalid results need to be factored into the implementation and operational costs of routine CD4+ T-lymphocyte testing.
To estimate the proportion of invalid results generated by a CD4+ T-lymphocyte analyser used by Médecins Sans Frontières (MSF) in field projects and identify factors associated with invalid results.
METHODS
We collated 25,616 CD4+ T-lymphocyte test results from 39 sites in nine countries for the years 2011 to 2013. Information about the setting, user, training, sampling technique and device repair history were obtained by questionnaire. The analyser performs a series of checks to ensure that all steps of the analysis are completed successfully; if not, an invalid result is reported. We calculated the proportion of invalid results by device and by operator. Regression analyses were used to investigate factors associated with invalid results.
FINDINGS
There were 3354 invalid test results (13.1%) across 39 sites, for 58 Alere PimaTM devices and 180 operators. The median proportion of errors per device and operator was 12.7% (interquartile range, IQR: 10.3-19.9) and 12.1% (IQR: 7.1-19.2), respectively. The proportion of invalid results varied widely by country, setting, user and device. Errors were not associated with settings, user experience or the number of users per device. Tests performed on capillary blood samples were significantly less likely to generate errors compared to venous whole blood.
CONCLUSION
The Alere Pima CD4+ analyser generated a high proportion of invalid test results, across different countries, settings and users. Most error codes could be attributed to the operator, but the exact causes proved difficult to identify. Invalid results need to be factored into the implementation and operational costs of routine CD4+ T-lymphocyte testing.
Journal Article > ResearchFull Text
PLOS One. 15 December 2015; Volume 10 (Issue 12); e0144656.; DOI:10.1371/journal.pone.0144656
Ardizzoni E, Fajardo E, Saranchuk P, Casenghi M, Page AL, et al.
PLOS One. 15 December 2015; Volume 10 (Issue 12); e0144656.; DOI:10.1371/journal.pone.0144656
BACKGROUND
The Xpert® MTB/RIF (Xpert) is an automated molecular test for simultaneous detection of tuberculosis (TB) and rifampicin resistance, recommended by the World Health Organization as the preferred diagnostic method for individuals presumed to have multi-drug resistant TB (MDR-TB) or HIV-associated TB. We describe the performance of Xpert and key lessons learned during two years of implementation under routine conditions in 33 projects located in 18 countries supported by Médecins Sans Frontières across varied geographic, epidemiological and clinical settings.
METHODS
Xpert was used following three strategies: the first being as the initial test, with microscopy in parallel, for all presumptive TB cases; the second being only for patients at risk of MDR-TB, or with HIV- associated TB, or presumptive paediatric TB; and the third being as the initial test for these high-risk patients plus as an add-on test to microscopy in others. Routine laboratory data were collected, using laboratory registers. Qualitative data such as logistic aspects, human resources, and tool acceptance were collected using a questionnaire.
FINDINGS
In total, 52,863 samples underwent Xpert testing from April 2011 to December 2012. The average MTB detection rate was 18.5%, 22.3%, and 11.6% for the three different strategies respectively. Analysis of the results on samples tested in parallel showed that using Xpert as add-on test to microscopy would have increased laboratory TB confirmation by 49.7%, versus 42.3% for Xpert replacing microscopy. The main limitation of the test was the high rate of inconclusive results, which correlated with factors such as defective modules, cartridge version (G3 vs. G4) and staff experience. Operational and logistical hurdles included infrastructure renovation, basic computer training, regular instrument troubleshooting and maintenance, all of which required substantial and continuous support.
CONCLUSION
The implementation of Xpert was feasible and significantly increased TB detection compared to microscopy, despite the high rate of inconclusive results. Xpert implementation was accompanied by considerable operational and logistical challenges. To further decentralize diagnosis, simpler, low-cost TB technologies well-suited to low-resource settings are still urgently needed.
The Xpert® MTB/RIF (Xpert) is an automated molecular test for simultaneous detection of tuberculosis (TB) and rifampicin resistance, recommended by the World Health Organization as the preferred diagnostic method for individuals presumed to have multi-drug resistant TB (MDR-TB) or HIV-associated TB. We describe the performance of Xpert and key lessons learned during two years of implementation under routine conditions in 33 projects located in 18 countries supported by Médecins Sans Frontières across varied geographic, epidemiological and clinical settings.
METHODS
Xpert was used following three strategies: the first being as the initial test, with microscopy in parallel, for all presumptive TB cases; the second being only for patients at risk of MDR-TB, or with HIV- associated TB, or presumptive paediatric TB; and the third being as the initial test for these high-risk patients plus as an add-on test to microscopy in others. Routine laboratory data were collected, using laboratory registers. Qualitative data such as logistic aspects, human resources, and tool acceptance were collected using a questionnaire.
FINDINGS
In total, 52,863 samples underwent Xpert testing from April 2011 to December 2012. The average MTB detection rate was 18.5%, 22.3%, and 11.6% for the three different strategies respectively. Analysis of the results on samples tested in parallel showed that using Xpert as add-on test to microscopy would have increased laboratory TB confirmation by 49.7%, versus 42.3% for Xpert replacing microscopy. The main limitation of the test was the high rate of inconclusive results, which correlated with factors such as defective modules, cartridge version (G3 vs. G4) and staff experience. Operational and logistical hurdles included infrastructure renovation, basic computer training, regular instrument troubleshooting and maintenance, all of which required substantial and continuous support.
CONCLUSION
The implementation of Xpert was feasible and significantly increased TB detection compared to microscopy, despite the high rate of inconclusive results. Xpert implementation was accompanied by considerable operational and logistical challenges. To further decentralize diagnosis, simpler, low-cost TB technologies well-suited to low-resource settings are still urgently needed.
Journal Article > ResearchFull Text
PLOS One. 3 April 2020; Volume 15 (Issue 4); e0230453.; DOI:10.1371/journal.pone.0230453.
Ndlovu Z, Massaquoi L, Bangwen NE, Batumba JN, Bora RU, et al.
PLOS One. 3 April 2020; Volume 15 (Issue 4); e0230453.; DOI:10.1371/journal.pone.0230453.
BACKGROUND
In sub-Saharan Africa, a third of people starting antiretroviral therapy and majority of patients returning to HIV-care after disengagement, present with advanced HIV disease (ADH), and are at high risk of mortality. Simplified and more affordable point-of-care (POC) diagnostics are required to increase access to prompt CD4 cell count screening for ambulatory and asymptomatic patients. The Visitect CD4 Lateral Flow Assay (LFA) is a disposable POC test, providing a visually interpreted result of above or below 200 CD4cells/mm3. This study evaluated the diagnostic performance of this index test.
METHODS
Consenting patients above 18years of age and eligible for CD4 testing were enrolled in Nsanje district hospital (Malawi), Gutu mission hospital (Zimbabwe) and Centre hopitalier de Kabinda (DRC). A total of 708 venous blood samples were tested in the index test and in the BD FACSCount assay (reference test method) in the laboratories (Phase 1) to determine diagnostic accuracy. A total of 433 finger-prick (FP) samples were tested on the index test at POC by clinicians (Phase 2) and a self-completed questionnaire was administered to all testers to explore usability of the index test.
RESULTS
Among 708 patients, 67.2% were female and median CD4 was 297cells/mm3. The sensitivity of the Visitect CD4 LFA using venous blood in the laboratory was 95.0% [95% CI: 91.3-97.5] and specificity was 81.9% [95% CI: 78.2-85.2%]. Using FP samples, the sensitivity of the Visitect CD4 LFA was 98.3% [95% CI: 95.0-99.6] and specificity was 77.2% [95% CI: 71.6-82.2%]. Usability of the Visitect CD4 LFA was high across the study sites with 97% successfully completed tests. Due to the required specific multiple incubation and procedural steps during the Visitect CD4 LFA testing, few health workers (7/26) were not confident to manage testing whilst multi-tasking in their clinical work.
CONCLUSIONS
Visitect CD4 LFA is a promising test for decentralized CD4 screening in resource-limited settings, without access to CD4 testing and and it can trigger prompt management of patients with AHD. Lay health cadres should be considered to conduct Visitect CD4 LFA testing in PHCs as well as coordinating all other POC quality assurance.
In sub-Saharan Africa, a third of people starting antiretroviral therapy and majority of patients returning to HIV-care after disengagement, present with advanced HIV disease (ADH), and are at high risk of mortality. Simplified and more affordable point-of-care (POC) diagnostics are required to increase access to prompt CD4 cell count screening for ambulatory and asymptomatic patients. The Visitect CD4 Lateral Flow Assay (LFA) is a disposable POC test, providing a visually interpreted result of above or below 200 CD4cells/mm3. This study evaluated the diagnostic performance of this index test.
METHODS
Consenting patients above 18years of age and eligible for CD4 testing were enrolled in Nsanje district hospital (Malawi), Gutu mission hospital (Zimbabwe) and Centre hopitalier de Kabinda (DRC). A total of 708 venous blood samples were tested in the index test and in the BD FACSCount assay (reference test method) in the laboratories (Phase 1) to determine diagnostic accuracy. A total of 433 finger-prick (FP) samples were tested on the index test at POC by clinicians (Phase 2) and a self-completed questionnaire was administered to all testers to explore usability of the index test.
RESULTS
Among 708 patients, 67.2% were female and median CD4 was 297cells/mm3. The sensitivity of the Visitect CD4 LFA using venous blood in the laboratory was 95.0% [95% CI: 91.3-97.5] and specificity was 81.9% [95% CI: 78.2-85.2%]. Using FP samples, the sensitivity of the Visitect CD4 LFA was 98.3% [95% CI: 95.0-99.6] and specificity was 77.2% [95% CI: 71.6-82.2%]. Usability of the Visitect CD4 LFA was high across the study sites with 97% successfully completed tests. Due to the required specific multiple incubation and procedural steps during the Visitect CD4 LFA testing, few health workers (7/26) were not confident to manage testing whilst multi-tasking in their clinical work.
CONCLUSIONS
Visitect CD4 LFA is a promising test for decentralized CD4 screening in resource-limited settings, without access to CD4 testing and and it can trigger prompt management of patients with AHD. Lay health cadres should be considered to conduct Visitect CD4 LFA testing in PHCs as well as coordinating all other POC quality assurance.
Journal Article > ResearchFull Text
BMC Infect Dis. 14 November 2018; Volume 18 (Issue 1); DOI:10.1186/s12879-018-3474-1
Mpala Q, Maphalala G, Uribe PAD, de la Tour R, Kalombola S, et al.
BMC Infect Dis. 14 November 2018; Volume 18 (Issue 1); DOI:10.1186/s12879-018-3474-1
Viral load (VL) testing is being scaled up in resource-limited settings. However, not all commercially available VL testing methods have been evaluated under field conditions. This study is one of a few to evaluate the Biocentric platform for VL quantification in routine practice in Sub-Saharan Africa.
Journal Article > ResearchFull Text
J Acquir Immune Defic Syndr. 1 September 2019; Volume 82 (Issue 1); 96-104.; DOI:10.1097/QAI.0000000000002101
Kerschberger B, Ntshalintshali N, Mpala Q, Diaz Uribe PA, Maphalala G, et al.
J Acquir Immune Defic Syndr. 1 September 2019; Volume 82 (Issue 1); 96-104.; DOI:10.1097/QAI.0000000000002101
BACKGROUND
To assess the performance and suitability of dried blood spot (DBS) sampling using filter paper to collect blood for viral load (VL) quantification under routine conditions.
METHODS
We compared performance of DBS VL quantification using the Biocentric method with plasma VL quantification using Roche and Biocentric as reference methods. Adults (≥18 years) were enrolled at 2 health facilities in Eswatini from October 12, 2016 to March 1, 2017. DBS samples were prepared through finger-prick by a phlebotomist (DBS-1), and through the pipetting of whole venous blood by a phlebotomist (DBS-2) and by a laboratory technologist (DBS-3). We calculated the VL-testing completion rate, correlation, and agreement, as well as diagnostic accuracy estimates at the clinical threshold of 1000 copies/mL.
RESULTS
Of 362 patients enrolled, 1066 DBS cards (DBS-1: 347; DBS-2: 359; DBS-3: 360) were tested. Overall, test characteristics were comparable between DBS-sampling methods, irrespective of the reference method. The Pearson correlation coefficients ranged from 0.67 to 0.82 (P < 0.001) for different types of DBS sampling using both reference methods, and the Bland-Altman difference ranged from 0.15 to 0.30 log10 copies/mL. Sensitivity estimates were from 85.3% to 89.2% and specificity estimates were from 94.5% to 98.6%. The positive predictive values were between 87.0% and 96.5% at a prevalence of 30% VL elevations, and negative predictive values were between 93.7% and 95.4%.
CONCLUSIONS
DBS VL quantification using the newly configured Biocentric method can be part of contextualized VL-testing strategies, particularly for remote settings and populations with higher viral failure rates.
To assess the performance and suitability of dried blood spot (DBS) sampling using filter paper to collect blood for viral load (VL) quantification under routine conditions.
METHODS
We compared performance of DBS VL quantification using the Biocentric method with plasma VL quantification using Roche and Biocentric as reference methods. Adults (≥18 years) were enrolled at 2 health facilities in Eswatini from October 12, 2016 to March 1, 2017. DBS samples were prepared through finger-prick by a phlebotomist (DBS-1), and through the pipetting of whole venous blood by a phlebotomist (DBS-2) and by a laboratory technologist (DBS-3). We calculated the VL-testing completion rate, correlation, and agreement, as well as diagnostic accuracy estimates at the clinical threshold of 1000 copies/mL.
RESULTS
Of 362 patients enrolled, 1066 DBS cards (DBS-1: 347; DBS-2: 359; DBS-3: 360) were tested. Overall, test characteristics were comparable between DBS-sampling methods, irrespective of the reference method. The Pearson correlation coefficients ranged from 0.67 to 0.82 (P < 0.001) for different types of DBS sampling using both reference methods, and the Bland-Altman difference ranged from 0.15 to 0.30 log10 copies/mL. Sensitivity estimates were from 85.3% to 89.2% and specificity estimates were from 94.5% to 98.6%. The positive predictive values were between 87.0% and 96.5% at a prevalence of 30% VL elevations, and negative predictive values were between 93.7% and 95.4%.
CONCLUSIONS
DBS VL quantification using the newly configured Biocentric method can be part of contextualized VL-testing strategies, particularly for remote settings and populations with higher viral failure rates.
Journal Article > ResearchFull Text
J Acquir Immune Defic Syndr. 25 July 2013; Volume 64 (Issue 2); DOI:10.1097/QAI.0b013e3182a61e63
Pannus P, Fajardo E, Metcalf CJ, Coulborn R M, Duran LT, et al.
J Acquir Immune Defic Syndr. 25 July 2013; Volume 64 (Issue 2); DOI:10.1097/QAI.0b013e3182a61e63
: Rollout of routine HIV-1 viral load monitoring is hampered by high costs and logistical difficulties associated with sample collection and transport. New strategies are needed to overcome these constraints. Dried blood spots from finger pricks have been shown to be more practical than the use of plasma specimens, and pooling strategies using plasma specimens have been demonstrated to be an efficient method to reduce costs. This study found that combination of finger-prick dried blood spots and a pooling strategy is a feasible and efficient option to reduce costs, while maintaining accuracy in the context of a district hospital in Malawi.
Journal Article > ReviewFull Text
J Int AIDS Soc. 9 October 2012; Volume 15 (Issue 2); 17324.; DOI:10.7448/IAS.15.2.17324
Roberts TR, Bygrave H, Fajardo E, Ford NP
J Int AIDS Soc. 9 October 2012; Volume 15 (Issue 2); 17324.; DOI:10.7448/IAS.15.2.17324
Though the advantages of routine virological monitoring for patients on anti-retroviral therapy have been established, cost and complexity limit its full implementation. Monitoring is important for diagnosing virological failure early on, before the development of drug resistance mutations, and to trigger early adherence interventions. Simple and cost-effective viral load tests that facilitate simplification and decentralization of testing and strategies, such as the use of dried blood spots and pooled sample testing, which further aid simplification, are becoming available. In addition, replacing immunological monitoring with virological monitoring in non-viremic patients in a phased manner will reduce the costs associated with dual immuno-virological monitoring. Going forward, the simplification of testing paired with price reducing strategies that will allow for healthy competition between multiple manufacturers will enable the implementation of viral load testing in resource-poor settings. It is important that future HIV and AIDS treatment guidelines provide clear recommendations for routine virological monitoring and that governments and donors fund the implementation of accurate and operationally proven testing platforms in a comprehensive manner.
Journal Article > ResearchFull Text
PLOS One. 2 March 2018; Volume 13 (Issue 3); DOI:10.1371/journal.pone.0193577
Ndlovu M, Fajardo E, Mbofana F, Maparo TMS, Garone DB, et al.
PLOS One. 2 March 2018; Volume 13 (Issue 3); DOI:10.1371/journal.pone.0193577
HIV Viral Load and Early Infant Diagnosis technologies in many high burden settings are restricted to centralized laboratory testing, leading to long result turnaround times and patient attrition. GeneXpert (Cepheid, CA, USA) is a polyvalent near point-of-care platform and is widely implemented for Xpert MTB/RIF diagnosis. This study sought to evaluate the operational feasibility of integrated HIV VL, EID and MTB/RIF testing in new GeneXpert platforms.
Journal Article > ResearchFull Text
Public Health Action. 21 September 2019
England K, Masini T, Fajardo E
Public Health Action. 21 September 2019
The World Health Organization (WHO) currently recommends Xpert® MTB/RIF as the initial test for all people with presumptive tuberculosis (TB). A number of challenges have been reported, however, in using this technology, particularly in low-resource settings. Here we examine these challenges, and provide our perspective of the barriers to Xpert scale-up as assessed through a survey in 16 TB burden countries in which the Médecins Sans Frontières is present. We observed that the key barriers to scale-up include a lack of policy adoption and implementation of WHO recommendations for the use of Xpert, resulting from high costs, poor sensitisation of clinical staff and a high turnover of trained laboratory
staff; insufficient service and maintenance provision provided by the manufacturer; and inadequate resources for sustainability and expansion. Funding is a critical issue as countries begin to transition out of support from the Global Fund. While it is clear that there is still an urgent need for research into and development of a rapid, affordable point-of-care test for TB that is truly adapted for use in low-resource settings, countries in the meantime need to develop functional and sustainable Xpert networks in order to close the existing diagnostic gap.
staff; insufficient service and maintenance provision provided by the manufacturer; and inadequate resources for sustainability and expansion. Funding is a critical issue as countries begin to transition out of support from the Global Fund. While it is clear that there is still an urgent need for research into and development of a rapid, affordable point-of-care test for TB that is truly adapted for use in low-resource settings, countries in the meantime need to develop functional and sustainable Xpert networks in order to close the existing diagnostic gap.
Journal Article > CommentaryFull Text
Lancet HIV. 27 May 2020; Volume 7 (Issue 7); e514-520.; DOI:10.1016/S2352-3018(20)30101-6.
Ndlovu Z, Burton R, Stewart RC, Bygrave H, Roberts TR, et al.
Lancet HIV. 27 May 2020; Volume 7 (Issue 7); e514-520.; DOI:10.1016/S2352-3018(20)30101-6.