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|colspan="1" style = "font-size:130%; color:black; background: FFFAFA"|<span style="color:black>'''RDT Quiz A Q3'''</span>
</br><span style="font-size:90%">Both microscopy and RDT tests can be used to diagnose malaria, and the two test types are often used together. However, the tests are not identical in their characteristics and have different strengths and weaknesses.</span></br></br>
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{<span style="font-size:90%">When comparing microscopy and RDT tests for malaria which of the following statements are correct? ('''select all true statements''')</br></br>
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|colspan="1" style = "font-size:130%; color:black; background: FFFAFA"|<span style="color:black>'''RDT Quiz A'''</span>
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{3. When comparing RDT tests and morphology in the diagnosis of malaria which statements are true?
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- RDT tests offer superior species identification compared with microscopy
- <span style="font-size:90%">RDT gives superior species identification
+ Well-trained microscopists diagnose malaria with equivalent or better sensitivity than RDT
+ <span style="font-size:90%">Microscopy is more sensitivity than RDT
+ MDT tests offer a more rapid initial diagnosis
+ <span style="font-size:90%">RDT provides a more rapid diagnosis
+ RDT tests may be a preferred choice in some low-income countries
+ <span style="font-size:90%">RDT may be preferred in some settings
- RDT tests provide a more accurate assessment of the % of infected red cells
- <span style="font-size:90%">RDT accurately assesses parasitaemia
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! colspan="1" | Explanation of correct answer (click "Expand")
! colspan="1" | Explanation of correct answer (click "Expand")
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|<span style="color:navy>'''The value of RDT tests compared with microscopy: thick blood films'''</span>
|<span style="font-size:90%">''Short answer taken from section "Microscopy vs RDT" (see the section for full details and links).</br></br>''In ideal conditions a well-trained microscopist with experience in malaria, viewing a well-prepared thick blood film using a good quality microscope may detect with equal or better sensitivity than an RDT test.</span>
 
<span style="font-size:90%">It is important in all cases however to understand the limitations of the test used (microscopy or RDT) in terms of species identiication and sensitivity.</span>
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<span style="font-size:90%">In less ideal conditions where equipment, staining quality, or microscopic experience is less good, then RDTs may have equivalent or superior sensitivity to microscopy (including many malarial endemic regions where microscopy may be unavailable or where the sensitivity of microscopy is limited by training, equipment or facilities). RDTs aso provide a more rapid turnaround time allowing emergency use and rapid decision-making.</span>  
<span style="font-size:90%">In ideal conditions a well-trained microscopist with experience in malaria, viewing a well-prepared thick blood film using a good quality microscope may detect better than 1 infected cell per 1000 total red cells. This is equivalent to around 50 parasites/ul. However, in practice it is estimated that a less experienced microscopist in equivalent conditions may acheive less sensitivity - perhaps 1 parasite in 100 red cells - equivalent to 500 parasites/μl. Both these outcomes are as good or better than an RDT test for detecting ''P.falciparum'', and exceed what might be expected for other malaria species.</span>
<span style="font-size:90%">In less ideal conditions where equipment, staining quality, or microscopic experience is less good, then RDTs may have equivalent or superior sensitivity to microscopy. This includes many malarial endemic regions where microscopy may be unavailable or where the sensitivity of microscopy is limited by training, equipment or facilities.</span>  
 
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<span style="font-size:90%">For species identification thin films are preferred to thick films or RTDS (including mixed infections), as they also allow more accurate identification of sepecies and the % of infected red-cells (for ''P.falciparum'' or ''P.knowlesi'').</span>
<span style="color:navy>'''The value of RDT tests compared with microscopy: thin blood films'''</span>
 
<span style="font-size:90%">Thin films may provide similar sensitivity for diagnosis to thick films to a routine laboratory where an experienced morphologist has sufficient time and experience and is able to follow recommended practices by examining a large number of microscopic fields. The thin-film format may be preferred by users are less familiar with thick films and feel more comfortable with thin film appearances. However, this is not the currently recommended practice for diagnosis.</br></br>Thin films do however offer particular advantages for the assessment of cases once a diagnosis of malaria has ben made:</span>
 
<span style="font-size:90%">(1) For species identification thin films are preferred to thick films or RTDS (including mixed infections) as they allow accurate assesment of sepcies specific features</span>
*<span style="font-size:90%">Where cases require the % of infected red-cells to be determined (''P.falciparum'' or ''P.knowlesi'') this is much more accurately assessed by thin film.</span>
 
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<span style="color:navy>'''Under what circumstances may a RDT be preferred?'''</span>
 
<span style="font-size:90%">(1) RDT tests are less affected by operator skill, facilities or training. They may provide a diagnostic sensitivity that is as good or better than morphology where expertise is limited, and may be the only choice where conditions do not allow microscopy.</br>(2) RDTs provide a more rapid turnaround time allowing emergency use and rapid decision-making.</br>(3) When used together with morphology RDTs may help increase diagnostic confidence compared with when either is used alone.</br>(4) The use of RDTs may provide an overall cheaper diagnostic alternative in low-income countries.</span>
 
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|colspan="1" style = "font-size:90%; color:black|<span style="color:black>[[RDT_Quiz_A_Q4|Go to next question (4 of 5)]]</span>

Latest revision as of 10:26, 26 November 2024


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RDT Quiz A Q3


Both microscopy and RDT tests can be used to diagnose malaria, and the two test types are often used together. However, the tests are not identical in their characteristics and have different strengths and weaknesses.

When comparing microscopy and RDT tests for malaria which of the following statements are correct? (select all true statements)

RDT gives superior species identification
Microscopy is more sensitivity than RDT
RDT provides a more rapid diagnosis
RDT may be preferred in some settings
RDT accurately assesses parasitaemia


Explanation of correct answer (click "Expand")
Short answer taken from section "Microscopy vs RDT" (see the section for full details and links).

In ideal conditions a well-trained microscopist with experience in malaria, viewing a well-prepared thick blood film using a good quality microscope may detect with equal or better sensitivity than an RDT test.

In less ideal conditions where equipment, staining quality, or microscopic experience is less good, then RDTs may have equivalent or superior sensitivity to microscopy (including many malarial endemic regions where microscopy may be unavailable or where the sensitivity of microscopy is limited by training, equipment or facilities). RDTs aso provide a more rapid turnaround time allowing emergency use and rapid decision-making.


For species identification thin films are preferred to thick films or RTDS (including mixed infections), as they also allow more accurate identification of sepecies and the % of infected red-cells (for P.falciparum or P.knowlesi).


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