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Plasmodium falciparum lactate dehydrogenase (PfLDH): Difference between revisions

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The pLDH assays identify enzymes specific to the malaria glycolytic pathway, three forms of test antigen exist: a PpanLDH which has capability to detect all forms of malaria (see separate description) and "species specific" forms that detect forms found only in particular malaria forms: a ''P.falciparum''-specific form (PfLDH) and a ''P.vavax''-specific form (PvLDH).  
The pLDH assays identify enzymes of the malaria glycolytic pathway, the proteins are distinct from human forms of LDH allowing them to be identified by RDT tests. There are also species specific features.


This means that there are three forms of test antigen:
*PpanLDH - this potentially detects all forms of malaria although sensitivity varies between species
*PfLDH - specifically detects a form expressed by ''P.falciparum'' detecting the species with good sensitivity
*PvLDH - detecting the parasite form of LDH that is specific for ''P.vivax'' 


The PfLDH has excellent sensitivity at high parasitaemia, with sensitivity that may meet or exceed 90%. However, at lower parasite levels (<1000 parasites/ μL) sensitivity of PfLDH may be lower than HRP2 (around 45%).  
Practical use
 
PfLDH: excellent sensitivity at high parasitaemia that may meet or exceed 90%. However, at lower parasite levels (<1000 parasites/ μL) sensitivity of PfLDH may be lower than HRP2 (around 45%). Two advantages over HRP2 sould be considered. First, this conserved antigen does not have reported gene-delection so may be an effective choice where malaria arises in ares with high rates of HRP2 deletion. Second, the antgen is realtively rapidly cleared from the blood, so PfLDH has value in testing rsponse to treatment or for malaria testing in recently infected patients.  





Revision as of 10:19, 1 August 2024


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Use of PfLDH in diagnosis


The pLDH assays identify enzymes of the malaria glycolytic pathway, the proteins are distinct from human forms of LDH allowing them to be identified by RDT tests. There are also species specific features.

This means that there are three forms of test antigen:

  • PpanLDH - this potentially detects all forms of malaria although sensitivity varies between species
  • PfLDH - specifically detects a form expressed by P.falciparum detecting the species with good sensitivity
  • PvLDH - detecting the parasite form of LDH that is specific for P.vivax

Practical use

PfLDH: excellent sensitivity at high parasitaemia that may meet or exceed 90%. However, at lower parasite levels (<1000 parasites/ μL) sensitivity of PfLDH may be lower than HRP2 (around 45%). Two advantages over HRP2 sould be considered. First, this conserved antigen does not have reported gene-delection so may be an effective choice where malaria arises in ares with high rates of HRP2 deletion. Second, the antgen is realtively rapidly cleared from the blood, so PfLDH has value in testing rsponse to treatment or for malaria testing in recently infected patients.



Characteristics of HRP2 to be aware of


A much more effective test of cure as the antigen is cleared more rapidly after effective treatment

Less affected by prozne and no mutation