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Interpretation guide: MULTI BAND tests: Difference between revisions

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(Created page with "Invalid test No band appears in the control area Invalid test: do not interpret, consider if test was incorrectly performed or incorrectly stored For valid tests (1) A band appears in the species-specific area only Most common: the species is present and no other species is present Possible alternatives: There is a dual infection but the second species is not detected by the pan-species antibody* This is a false positive band* (2) No band present in species-specific...")
 
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Invalid test
{{DISPLAYTITLE:<span style="position: absolute; clip: rect(1px 1px 1px 1px); clip: rect(1px, 1px, 1px, 1px);">{{FULLPAGENAME}}</span>}}
No band appears in the control area
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Invalid test: do not interpret, consider if test was incorrectly performed or incorrectly stored
'''Navigation'''</br>
<span style="font-size:90%">[[MalariaETC Index|Main Malaria Index]]''</span></br>
<span style="font-size:90%">>[[Rapid diagnostic tests (RDTs)|RDT main page]]''</span></br>
<span style="font-size:90%">>>This page: '''Multi band RDT tests'''</span>
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<span style="font-size:160%; color:navy">Multi-band RDT tests</br></span>
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For valid tests
{| class="wikitable" style="border-style: none; border-width: 2px; border-color: gainsboro; color:black"
(1) A band appears in the species-specific area only
|colspan="1" style = "font-size:100%; color:black; background: gainsboro |'''RESULT PATTERN 1'''
Most common: the species is present and no other species is present
|}
Possible alternatives:
<span style="font-size:90%; color:maroon">These are '''invalid tests''' No band appears in the control area (black arrow)</span>: </br></br>
There is a dual infection but the second species is not detected by the pan-species antibody*
This is a false positive band*


(2) No band present in species-specific area
<gallery mode="nolines" widths=80px heights=160px>
Most common: the species is not present
File:RDT_multi_fail1.jpg|<span style="font-size:90%"></span>|link={{filepath:RDT_multi_fail1.jpg}}
Possible alternatives:
File:RDT_multi_fail2.jpg|<span style="font-size:90%"></span>|link={{filepath:RDT_multi_fail1.jpg}}
A faint band was present but not seen by observer*
File:RDT_multi_fail3.jpg|<span style="font-size:90%"></span>|link={{filepath:RDT_multi_fail1.jpg}}
The species is present but not detected due to low parasite concentration (link to reasons)
File:RDT_multi_fail4.jpg|<span style="font-size:90%"></span>|link={{filepath:RDT_multi_fail1.jpg}}
The species is present but not detected for technical reasons
</gallery>
The species is present, but there is gene deletion of the target antigen (HRP2 tests)
<span style="font-size:90%">Irrespective of whether any other bands are present, this is always an invalid test: '''do not interpret.''' Report as failed test</br>Action:</span>
The species is present but exceeds test capacity due to very high parasite Pyrome effect (mainly HRP2 tests)
*<span style="font-size:90%">Repeat the test</br></span>
*<span style="font-size:90%">Consider the reasons for [ [[Practical reasons for test failure 1|test failure]] ]</span>
</br>


(3) A band appears in the pan-malaria area only
The most common cause is infection is present with a malaria species not detected by the specific antibody
Possible alternatives:
The specific band has failed (see causes above) but pan-malaria antigen still detects that species
No malaria is present and the band in the pan-malaria area is a false positive (cross reaction)


{| class="wikitable" style="border-style: none; border-width: 2px; border-color: gainsboro; color:black"
|colspan="1" style = "font-size:100%; color:black; background: gainsboro |'''RESULT PATTERN 2'''
|}


(4) A band appears in both the species-specific and pan malarial area
There has a '''valid control line''' (black arrow) showing a technically successful test, but '''no malaria bands are detected''' either the species specifc or pan malaria areas.


A single specific species and is detected by specific and pan-malaria antigens (95%)
 
There are two species present in the sample (5%)
<gallery mode="nolines" widths=80px heights=160px>
False positive result in both bands (least common cause)
File:RDT_multi_neg.jpg|<span style="font-size:90%"></span>|link={{filepath:RDT_multi_neg.jpg}}
</gallery>
 
<span style="font-size:90%">'''Most likely interpretation:''' No malaria parasites are present</br></span>
 
<span style="font-size:90%">'''Less likely but possible interpretations:'''</span>
*<span style="font-size:90%">Malaria infection is present, but is not detected because it is below the detection limit of the test</span>
*<span style="font-size:90%">Bands are present but may be faint and not seen by the operator</span>
</br>
 
 
{| class="wikitable" style="border-style: none; border-width: 2px; border-color: gainsboro; color:black"
|colspan="1" style = "font-size:100%; color:black; background: gainsboro |'''RESULT PATTERN 3'''
|}
 
<span style="font-size:90%">The test has '''valid control line''' (black arrow) and has bands in the '''pan-specific area''' and the '''species specific area''' (red arrows)</span>
 
 
<gallery mode="nolines" widths=80px heights=160px>
File:RDT_multi_posPF1.jpg|<span style="font-size:90%"></span>|link={{filepath:RDT_multi_posPF1.jpg}}
</gallery>
 
<span style="font-size:90%">'''Most likely interpretation:''' The single species detected by the species specific band is present (this same species is also detected the pan-malaria band)
 
<span style="font-size:90%">'''Less likely but possible interpretations:'''</span>
*<span style="font-size:90%">There are two species present in the sample (likelihood depends on country of origin, but is less likely) [ [[Co-infection with two species2|Co-infection with two species]] ]</span>
*<span style="font-size:90%">There is a false positive result causing both bands (unlikely) [ [[False positive reaction in RDT tests 2|False positive reaction in RDT tests]] ]</span>
 
 
 
{| class="wikitable" style="border-style: none; border-width: 2px; border-color: gainsboro; color:black"
|colspan="1" style = "font-size:100%; color:black; background: gainsboro |'''RESULT PATTERN 4'''
|}
 
<span style="font-size:90%">The test has '''valid control line''' (black arrow) and a '''band in the species-specific area only''' (red arrow)</span>
 
 
<gallery mode="nolines" widths=80px heights=160px>
File:RDT_multi_posPF2.jpg|<span style="font-size:90%"></span>|link={{filepath:RDT_multi_posPF2.jpg}}
</gallery>
 
<span style="font-size:90%">'''Most likely interpretation:''' The species detected by the test is present and is the only malaria species infecting the individual</br></span>
 
<span style="font-size:90%">'''Less likely but possible interpretations:'''</span>
*<span style="font-size:90%">There is a dual-species infection, but the second species was not detected by the pan-specific band [ [[Co-infection with two species2|Co-infection with two species]] ]</span>
*<span style="font-size:90%">There is no active malaria, but patient recently received successful treatment and the antigen has not yet cleared [ [[Clearance of parasite antigens from blood 2|Clearance of parasite antigens from blood]] ]</span>
*<span style="font-size:90%">The "specific band" is a false positive result (infrequent but observed) [ [[False positive reaction in RDT tests 2|False positive reaction in RDT tests]] ]</span>
</br>
 
 
 
{| class="wikitable" style="border-style: none; border-width: 2px; border-color: gainsboro; color:black"
|colspan="1" style = "font-size:100%; color:black; background: gainsboro |'''RESULT PATTERN 5'''
|}
 
 
<span style="font-size:90%">The test has '''valid control line''' (black arrow) and a '''band in the pan-specific area only''' (red arrow)</span>
<gallery mode="nolines" widths=80px heights=160px>
File:RDT_multi_pan1.jpg|<span style="font-size:90%"></span>|link={{filepath:RDT_multi_pan1.jpg}}
</gallery>
 
<span style="font-size:90%">'''Most likely interpretation:''' A malaria infection is detected (pan band), but is not caused by the species detected by the specific antibody (Sp band)</br></span>
 
<span style="font-size:90%">'''Less likely but possible interpretations:'''</span>
*<span style="font-size:90%">The species detected by the specific band is present (as a single infection or dual infection), but has not been detected by the specific band [ [[Prozone_effect_alt|Prozone-like effect]] ], [ [[HRP2_gene_deletion_alt|HRP2 gene deletion]] ]</span>
*<span style="font-size:90%">The "specific band" is a false positive result (infrequent but observed) [ [[False positive reaction in RDT tests 2|False positive reaction in RDT tests]] ]</span>
 
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Latest revision as of 15:17, 14 April 2025


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Multi-band RDT tests



RESULT PATTERN 1

These are invalid tests No band appears in the control area (black arrow):

Irrespective of whether any other bands are present, this is always an invalid test: do not interpret. Report as failed test
Action:



RESULT PATTERN 2

There has a valid control line (black arrow) showing a technically successful test, but no malaria bands are detected either the species specifc or pan malaria areas.


Most likely interpretation: No malaria parasites are present

Less likely but possible interpretations:

  • Malaria infection is present, but is not detected because it is below the detection limit of the test
  • Bands are present but may be faint and not seen by the operator



RESULT PATTERN 3

The test has valid control line (black arrow) and has bands in the pan-specific area and the species specific area (red arrows)


Most likely interpretation: The single species detected by the species specific band is present (this same species is also detected the pan-malaria band)

Less likely but possible interpretations:


RESULT PATTERN 4

The test has valid control line (black arrow) and a band in the species-specific area only (red arrow)


Most likely interpretation: The species detected by the test is present and is the only malaria species infecting the individual

Less likely but possible interpretations:



RESULT PATTERN 5


The test has valid control line (black arrow) and a band in the pan-specific area only (red arrow)

Most likely interpretation: A malaria infection is detected (pan band), but is not caused by the species detected by the specific antibody (Sp band)

Less likely but possible interpretations: