Table 2 Proposed Target Product Profile (TPP) for an IR-ML based system for parasitological surveillance of malaria (focusing on detecting parasites in vertebrate host)
Characteristics | Parasitological surveillance | ||||
|---|---|---|---|---|---|
Passive case detection in clinical settings (symptomatic cases) | Active case detection in field screening (asymptomatic cases) | ||||
Essential characteristics | Desired characteristics | Essential characteristics | Desired characteristics | ||
Scope | Intended use settings and contexts | As point-of-care test in malaria control settings | As point of care test in elimination and control settings | Malaria screening in moderate to high transmission settings | Can be used in low, moderate and high transmission settings |
Implementation level | District-level health facilities, other centralized facilities & research facilities | Can be used in peripheral health facilities, e.g., dispensaries, health posts & health centres | Used for surveys in research facilities | Routine parasitological surveys in district or regional hospitals | |
Types of spectrometers and durability | Bench-top units that require minimum electricity, and can operate 5 years or more with minimal maintenance | Off –the-shelf portable units with long-life battery; can be solar-powered; can operate for up to 10 years with minimal maintenance | Bench-top units that require minimum electricity, and can operate 5 years or more with minimal maintenance | Off –the-shelf portable units with long-life battery; can be solar-powered; can operate for up to 10 years with minimal maintenance | |
Technical performance | Can detect > 95% of positive P. falciparum cases in symptomatic individuals relative to RDT | Can detect > 99% of positive P. falciparum cases in symptomatic individuals relative to RDT or microscopy | Detects > 95% of positive P. falciparum cases in moderate to high transmission areas relative to microscopy or RDT or PCR | Detects > 95% of positive P. falciparum cases in low, moderate or high transmission areas relative to microscopy or PCR | |
Can identify > 95% of malaria-negative cases in febrile individuals relative to RDT | Can identify > 99% of malaria-negative cases in febrile individuals relative to RDT or microscopy | Can identify > 95% of malaria-negative cases in areas with moderate to high transmission relative to microscopy or RDT or PCR | Can identify > 99% of malaria-negative cases in low, moderate to high transmission areas relative to microscopy or PCR | ||
Resolution and accuracy of predictions | Achieves at least 95% accuracy compared to RDT or microscopy | Performance equivalent to microscopy or RDTs) in detecting P. falciparum & other malaria parasites | Has > 95% accuracy compared to RDT or microscopy in moderate high transmission sites | Performance matches PCR in detecting malaria parasites under low—high transmission | |
Technical performance | Lower limit of parasite detection (LOD) | 50–100 parasites/μl of blood; equivalent to microscopy & RDTs in respective settings | Less than 50 parasite/μl of blood; better than microscopy & RDTs in respective settings | 50–100 parasites/μl of blood; equivalent to microscopy and RDTs in respective settings | Less than 50 parasite/μl of blood; better than microscopy & RDTs; equivalent to PCR |
Temperature and humidity stability | Stable in ambient temperatures; can withstand occasional increases to 30 °C for short periods | Stable in ambient temperatures; withstands occasional increases to 35 °C for short periods | Stable in ambient temperatures and can withstand increases to 35 °C for short periods and varied humidity | Stable in ambient temperatures and can withstand increases to 45 °C for short periods and varied humidity | |
Operational aspects | Equipment & maintenance costs | Less than $ 30,000 per spectrometer; lasts > 5 years; costs < $100/yr to maintain | Less than $ 2000 per portable spectrometer; lasts up to 10 years; Costs < $50/Yr to maintain | Less than $ 30,000 per spectrometer; lasts > 5 years; costs < $100/yr to maintain | Less than $ 2000 per portable spectrometer; lasts up to 10 years; Costs < $50/Yr to maintain |
Sample handling costs | Costs < $0.1 per test | Costs < $0.01per test | Costs < $0.1 per test | Costs < $0.01per test | |
Test duration |  < 5 min |  < 1 min |  < 5 min |  < 1 min | |
Sample preservation and storage | Requires freezing, desiccants, RNAlater Uses must be less than 30Â days old | Can use any preservation method Samples can be older than 6Â months as long as preserved fresh | Freezing, desiccants or RNAlater; Samples must be less than 30Â days old | Any preservation method; Samples can be older than 6Â months as long as preserved fresh | |
Operational aspects | Human resources: Skills & training | Requires minimal training on sample handling, scanning & data interpretation | No more than 30Â min training needed to use, conduct the tests and read results | Requires minimal training on sample handling, scanning & data interpretation | No more than 30Â min training needed to use, conduct the tests and read results |
Type of sample | Wet or dry blood samples; presented as glass slides, on filter papers or as blood drops | Both blood and non-blood samples (saliva, urine, sweat or other samples collected non-invasively e.g. over the skin) | Wet or dry blood samples; presented as glass slides, on filter papers or as blood drops | Both blood and non-blood samples (saliva, urine, sweat or other samples collected non-invasively e.g. via skin) | |
Reagents | No reagents needed except for cleaning the instruments or sample collection | No reagents needed except for cleaning the instruments or sample collection | No reagents needed except for cleaning the instruments or sample collection | No reagents needed except for cleaning the instruments or sample collection | |