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Errors generated by a point-of-care CD4+ T-lymphocyte analyser: a retrospective observational study in nine countries.

Fajardo E, Metcalf C, Piriou E, Gueguen M, Maman D, Chaillet P, Cox V, Rumaney MB, Tunggal S, Kosack C, Roberts T - Bull. World Health Organ. (2015)

Bottom Line: 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.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.Tests performed on capillary blood samples were significantly less likely to generate errors compared to venous whole blood.

View Article: PubMed Central - PubMed

Affiliation: Médecins Sans Frontières (MSF), Southern Africa Medical Unit (SAMU), Waverly Business Park, 303 A&B, Cape Town, South Africa .

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus

Sources of error using the Alere Pima CD4+ analyser for CD4+ T-lymphocyte counts, (n=3354), nine countries, 2011–2013
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Figure 2: Sources of error using the Alere Pima CD4+ analyser for CD4+ T-lymphocyte counts, (n=3354), nine countries, 2011–2013

Mentions: The most common errors were code 850 (37.0%) and code 880 (18.0%). These errors can result from multiple causes (Fig. 1). Based on the error codes, the source of the error was the user (1542; 46.0%); user or device (1519; 45.3%); device (83; 2.5%); or sample (147; 4.4%); with the remaining 63 errors (1.9%) being of unknown origin (Fig. 2). For calibration tests using Pima beads, 2% generated errors (207/10 404), with error codes 203 and 840 being the most common.


Errors generated by a point-of-care CD4+ T-lymphocyte analyser: a retrospective observational study in nine countries.

Fajardo E, Metcalf C, Piriou E, Gueguen M, Maman D, Chaillet P, Cox V, Rumaney MB, Tunggal S, Kosack C, Roberts T - Bull. World Health Organ. (2015)

Sources of error using the Alere Pima CD4+ analyser for CD4+ T-lymphocyte counts, (n=3354), nine countries, 2011–2013
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581638&req=5

Figure 2: Sources of error using the Alere Pima CD4+ analyser for CD4+ T-lymphocyte counts, (n=3354), nine countries, 2011–2013
Mentions: The most common errors were code 850 (37.0%) and code 880 (18.0%). These errors can result from multiple causes (Fig. 1). Based on the error codes, the source of the error was the user (1542; 46.0%); user or device (1519; 45.3%); device (83; 2.5%); or sample (147; 4.4%); with the remaining 63 errors (1.9%) being of unknown origin (Fig. 2). For calibration tests using Pima beads, 2% generated errors (207/10 404), with error codes 203 and 840 being the most common.

Bottom Line: 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.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.Tests performed on capillary blood samples were significantly less likely to generate errors compared to venous whole blood.

View Article: PubMed Central - PubMed

Affiliation: Médecins Sans Frontières (MSF), Southern Africa Medical Unit (SAMU), Waverly Business Park, 303 A&B, Cape Town, South Africa .

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus