| Possible causes for poor test performance
Selection and procurement of MDTs
1. Quality of test design/production. There is significant variation of performance between tests, users are advised to check test performance (see WHO testing information available from [2].
2. Lot to lot variability. Variability between batches has been observed and should be considered if RDT performance is less than expected.
2. Heat stability of the RDT test storage
potential for degradation due to heat and humidity. Extended exposure to these conditions can drastically reduce the shelf life of RDTsRDT manufacturers recommend continuous product refrigeration, from the point of manufacture all the way to rural clinics and the point of use. However, in many developing countries, cold-chain continuity cannot be guaranteed. WHO analysis of commercially available malaria RDTs found that 37 out of 50 tests claimed stability ranges of 2–30°C, and that the remaining 13 tests claimed stability up to 40°C. [18] However, in many countries, ambient temperatures regularly exceed these limits.
3. Age of test/reagents
Operator-Specific Factors
Operator-Inappropriate placement of reagent or blood drop
Operator-Interpreting faint lineBy virtue of being targeted for use at the point-of-care, immunochromatographic RDTs must be amenable to facile and accurate interpretation by minimally trained operators. However, test lines are often subject to highly variable and user-dependent readings, which can be impacted by user biases, low signal contrast, and inadequate training materials.
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