Practical reasons for poor RDT performance - Revision history

Admin at 15:05, 6 October 2024

2024-10-06T15:05:20Z

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Admin at 18:40, 14 September 2024

2024-09-14T18:40:46Z

← Older revision		Revision as of 19:40, 14 September 2024
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	\|colspan="1" style = "font-size:100%; color:blasck; background: FFFAFA"\|<span style="color:navy>'''Practical considerations '''</span>		\|colspan="1" style = "font-size:100%; color:blasck; background: FFFAFA"\|<span style="color:navy>'''Practical considerations '''</span>

	<span style="font-size:90%">Bibilography: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]</span>		<span style="font-size:90%">Bibilography: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/], [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests]</span>


	<span style="font-size:90%">'''1. Selection and procurement of MDTs'''</br>		<span style="font-size:90%">'''1. Selection and procurement of MDTs'''</br>

	<span style="font-size:90%">(a) Quality of test design/production. There may be significant variation of performance between tests, users are advised to check test performance (see WHO testing information ~~available from [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests].~~</br>(b) Lot variability. Variability between different production batches has been observed and should be considered if RDT performance is less than expected.</br>		<span style="font-size:90%">(a) Quality of test design/production. There may be significant variation of performance between tests, users are advised to check test performance (see WHO testing information ref 2 above)</br>(b) Lot variability. Variability between different production batches has been observed and should be considered if RDT performance is less than expected.</br>

	<span style="font-size:90%">'''2. Stability and storage issues'''</br>		<span style="font-size:90%">'''2. Stability and storage issues'''</br>
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	<span style="font-size:90%">'''3. Operator training'''</br>		<span style="font-size:90%">'''3. Operator training'''</br>

	<span style="font-size:90%">(a)Problems in test usage may include inappropriate placement of test reagents or blood sample.</br>		<span style="font-size:90%">(a)Problems in test usage may include inappropriate placement of test reagents or blood sample on RDT.</br>(b)Poor interpretion of faint lines.</br>(c) Inadequate training or reference materials
	Poor interpretion of faint lines.</br>Inadequate training or reference materials

Admin at 13:06, 13 September 2024

2024-09-13T13:06:55Z

← Older revision		Revision as of 14:06, 13 September 2024
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	<span style="font-size:90%">(a)Problems in test usage may include inappropriate placement of test reagents or blood sample.</br>		<span style="font-size:90%">(a)Problems in test usage may include inappropriate placement of test reagents or blood sample.</br>
	Poor interpretion of faint lines.</br>Inadequate training or reference materials		Poor interpretion of faint lines.</br>Inadequate training or reference materials

	In the case of malarial RDTs, the WHO requires a panel detection score of 75% at a parasitaemia of 200 parasites/μl in order for the product to warrant endorsement. [16] However, the threshold for pyrogenic onset has been shown to vary from 10 to 200,000 parasites/μl, with 22% of patients developing their first acute fever at a parasite load below 200/μl. [75] Thus, even for the select assortment of commercial malaria RDTs demonstrating compliance with WHO standards, sufficiently low limits of detection have not been demonstrated for the early and accurate diagnosis of nascent infections, or of asymptomatic carriers.


	In order to improve test sensitivities when dealing with non-ideal biomarkers, manufacturers of RDTs often seek to use the multiplexed detection of distinct, species-specific antigens. In the case of malaria, RDTs are often multiplexed to detect HRP2 and the P. vivax variant of parasite lactate dehydrogenase (Pv-pLDH), to distinguish between infections by P. falciparum and P. vivax. Alternatively, tests can be multiplexed to select for Pf-pLDH and HRP2, which yields highly sensitive indications for falciparum malaria. [16] Multiplexed RDTs have also proven to be efficacious in discriminating between distinct diseases with non-specific symptomatic presentations.

Admin at 13:06, 13 September 2024

2024-09-13T13:06:19Z

← Older revision		Revision as of 14:06, 13 September 2024
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	{\| class="wikitable" style="widthe:90%; border-style: solid; border-width: 4px; color:black"		{\| class="wikitable" style="widthe:90%; border-style: solid; border-width: 4px; color:black"
	\|colspan="1" style = "font-size:100%; color:blasck; background: FFFAFA"\|<span style="color:navy>'''Practical considerations ~~for MDT use~~'''</span>		\|colspan="1" style = "font-size:100%; color:blasck; background: FFFAFA"\|<span style="color:navy>'''Practical considerations '''</span>

	Bibilography: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]		<span style="font-size:90%">Bibilography: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]</span>


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	<span style="font-size:90%">'''2. Stability and storage issues'''</br>		<span style="font-size:90%">'''2. Stability and storage issues'''</br>

	<span style="font-size:90%">(a) RDTs typically have a shelf-life of 18–24 months providing storage is appropriateR. (b) Tests can suffer degradation if stored in inappropriate heat or humidity: generally tests are stable in the range 2–30°C or higher, but these limits may be exceeded in many countries, and continuous product refrigeration to the point of use may not be guarenteed in developing countries.		<span style="font-size:90%">(a) RDTs typically have a shelf-life of 18–24 months providing storage is appropriateR.</br>(b) Tests can suffer degradation if stored in inappropriate heat or humidity: generally tests are stable in the range 2–30°C or higher, but these limits may be exceeded in many countries, and continuous product refrigeration to the point of use may not be guarenteed in developing countries.

			<span style="font-size:90%">'''3. Operator training'''</br>

			<span style="font-size:90%">(a)Problems in test usage may include inappropriate placement of test reagents or blood sample.</br>
			Poor interpretion of faint lines.</br>Inadequate training or reference materials

	~~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.

	In the case of malarial RDTs, the WHO requires a panel detection score of 75% at a parasitaemia of 200 parasites/μl in order for the product to warrant endorsement. [16] However, the threshold for pyrogenic onset has been shown to vary from 10 to 200,000 parasites/μl, with 22% of patients developing their first acute fever at a parasite load below 200/μl. [75] Thus, even for the select assortment of commercial malaria RDTs demonstrating compliance with WHO standards, sufficiently low limits of detection have not been demonstrated for the early and accurate diagnosis of nascent infections, or of asymptomatic carriers.		In the case of malarial RDTs, the WHO requires a panel detection score of 75% at a parasitaemia of 200 parasites/μl in order for the product to warrant endorsement. [16] However, the threshold for pyrogenic onset has been shown to vary from 10 to 200,000 parasites/μl, with 22% of patients developing their first acute fever at a parasite load below 200/μl. [75] Thus, even for the select assortment of commercial malaria RDTs demonstrating compliance with WHO standards, sufficiently low limits of detection have not been demonstrated for the early and accurate diagnosis of nascent infections, or of asymptomatic carriers.

Admin at 13:01, 13 September 2024

2024-09-13T13:01:24Z

← Older revision		Revision as of 14:01, 13 September 2024
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	<span style="font-size:90%">(a) Quality of test design/production. There may be significant variation of performance between tests, users are advised to check test performance (see WHO testing information available from [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests].</br>(b) Lot variability. Variability between different production batches has been observed and should be considered if RDT performance is less than expected.</br>		<span style="font-size:90%">(a) Quality of test design/production. There may be significant variation of performance between tests, users are advised to check test performance (see WHO testing information available from [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests].</br>(b) Lot variability. Variability between different production batches has been observed and should be considered if RDT performance is less than expected.</br>

	'''2. ~~Heat stability of the RDT test~~''' ~~storage~~</b>		<span style="font-size:90%">'''2. Stability and storage issues'''</br>
	~~RDT tests~~ can suffer degradation if stored in inappropriate heat or humidity~~. Generally~~ tests are stable in the range 2–30°C or ~~greater. However~~ these limits may be exceeded in many countries and ~~manufacturers recommend~~ continuous product refrigeration to the point of use~~. This~~ may ~~create problems for~~ developing countries ~~where cold-chain continuity cannot be guaranteed~~.
			<span style="font-size:90%">(a) RDTs typically have a shelf-life of 18–24 months providing storage is appropriateR. (b) Tests can suffer degradation if stored in inappropriate heat or humidity: generally tests are stable in the range 2–30°C or higher, but these limits may be exceeded in many countries, and continuous product refrigeration to the point of use may not be guarenteed in developing countries.



	~~'''3. Age of test or reagents'''</br>~~
	~~RDTs typically have a shelf-life of 18–24 months, which inludes time for distribution and use, providing storage is appropriate.~~

Admin at 12:55, 13 September 2024

2024-09-13T12:55:07Z

← Older revision		Revision as of 13:55, 13 September 2024
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	{\| class="wikitable" style="widthe:90%; border-style: solid; border-width: 4px; color:black"		{\| class="wikitable" style="widthe:90%; border-style: solid; border-width: 4px; color:black"
	\|colspan="1" style = "font-size:100%; color:~~black~~; background: FFFAFA"\|<span style="color:navy>'''Practical considerations for MDT use'''</span>		\|colspan="1" style = "font-size:100%; color:blasck; background: FFFAFA"\|<span style="color:navy>'''Practical considerations for MDT use'''</span>

	Bibilography: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]		Bibilography: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]

	<span style="font-size:90%">'''Selection and procurement of MDTs'''</br>
	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 [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests].</br>		<span style="font-size:90%">'''1. Selection and procurement of MDTs'''</br>
	2. Lot ~~to lot~~ variability. Variability between batches has been observed and should be considered if RDT performance is less than expected.</br>
			<span style="font-size:90%">(a) Quality of test design/production. There may be significant variation of performance between tests, users are advised to check test performance (see WHO testing information available from [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests].</br>(b) Lot variability. Variability between different production batches has been observed and should be considered if RDT performance is less than expected.</br>

	'''2. Heat stability of the RDT test''' storage</b>		'''2. Heat stability of the RDT test''' storage</b>

Admin at 12:52, 13 September 2024

2024-09-13T12:52:56Z

← Older revision		Revision as of 13:52, 13 September 2024
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	{\| class="wikitable" style="widthe:90%; border-style: solid; border-width: 4px; color:black"		{\| class="wikitable" style="widthe:90%; border-style: solid; border-width: 4px; color:black"
	\|colspan="1" style = "font-size:100%; color:black; background: FFFAFA"\|<span style="color:navy>'''~~The value of RDT compared with microscopy: thick blood films~~'''</span>		\|colspan="1" style = "font-size:100%; color:black; background: FFFAFA"\|<span style="color:navy>'''Practical considerations for MDT use'''</span>

	Bibilography: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]		Bibilography: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]

Admin at 12:52, 13 September 2024

2024-09-13T12:52:15Z

← Older revision		Revision as of 13:52, 13 September 2024
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	\|colspan="1" style = "font-size:100%; color:black; background: FFFAFA"\|<span style="color:navy>'''The value of RDT compared with microscopy: thick blood films'''</span>		\|colspan="1" style = "font-size:100%; color:black; background: FFFAFA"\|<span style="color:navy>'''The value of RDT compared with microscopy: thick blood films'''</span>

	~~see also~~: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]		Bibilography: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]

	<span style="font-size:90%">'''Selection and procurement of MDTs'''</br>		<span style="font-size:90%">'''Selection and procurement of MDTs'''</br>

Admin at 12:51, 13 September 2024

2024-09-13T12:51:46Z

← Older revision		Revision as of 13:51, 13 September 2024
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	see also: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]		see also: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4652944/]

	'''Selection and procurement of MDTs'''</br>		<span style="font-size:90%">'''Selection and procurement of MDTs'''</br>
	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 [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests].</br>		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 [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests].</br>
	2. Lot to lot variability. Variability between batches has been observed and should be considered if RDT performance is less than expected.</br>		2. Lot to lot variability. Variability between batches has been observed and should be considered if RDT performance is less than expected.</br>

Admin at 16:35, 12 September 2024

2024-09-12T16:35:33Z

← Older revision		Revision as of 17:35, 12 September 2024
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	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 [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests].</br>		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 [https://www.who.int/teams/global-malaria-programme/case-management/diagnosis/rapid-diagnostic-tests].</br>
	2. Lot to lot variability. Variability between batches has been observed and should be considered if RDT performance is less than expected.</br>		2. Lot to lot variability. Variability between batches has been observed and should be considered if RDT performance is less than expected.</br>

			'''2. Heat stability of the RDT test''' storage</b>
			RDT tests can suffer degradation if stored in inappropriate heat or humidity. Generally tests are stable in the range 2–30°C or greater. However these limits may be exceeded in many countries and manufacturers recommend continuous product refrigeration to the point of use. This may create problems for developing countries where cold-chain continuity cannot be guaranteed.

			'''3. Age of test or reagents'''</br>
			RDTs typically have a shelf-life of 18–24 months, which inludes time for distribution and use, providing storage is appropriate.


	~~'''2. Heat stability of the RDT test''' storage</b>~~
	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'''</br>~~
	Operator-Specific Factors		Operator-Specific Factors
	Operator-Inappropriate placement of reagent or blood drop		Operator-Inappropriate placement of reagent or blood drop
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	In order to improve test sensitivities when dealing with non-ideal biomarkers, manufacturers of RDTs often seek to use the multiplexed detection of distinct, species-specific antigens. In the case of malaria, RDTs are often multiplexed to detect HRP2 and the P. vivax variant of parasite lactate dehydrogenase (Pv-pLDH), to distinguish between infections by P. falciparum and P. vivax. Alternatively, tests can be multiplexed to select for Pf-pLDH and HRP2, which yields highly sensitive indications for falciparum malaria. [16] Multiplexed RDTs have also proven to be efficacious in discriminating between distinct diseases with non-specific symptomatic presentations.		In order to improve test sensitivities when dealing with non-ideal biomarkers, manufacturers of RDTs often seek to use the multiplexed detection of distinct, species-specific antigens. In the case of malaria, RDTs are often multiplexed to detect HRP2 and the P. vivax variant of parasite lactate dehydrogenase (Pv-pLDH), to distinguish between infections by P. falciparum and P. vivax. Alternatively, tests can be multiplexed to select for Pf-pLDH and HRP2, which yields highly sensitive indications for falciparum malaria. [16] Multiplexed RDTs have also proven to be efficacious in discriminating between distinct diseases with non-specific symptomatic presentations.

	~~RDTs typically have a shelf-life of 18–24 months, allowing sufficient time for delivery, distribution, and use in most settings~~.