Comparative Study on the effectiveness of PfHRP2 and PAN pLDH RDTs in Routine Malaria Diagnosis of Clinically Suspected Malaria Patients in Katsina State

Katsina State is a malaria-endemic zone, with Plasmodium falciparum being the most prevalent species. Rapid Diagnostic Tests (RDTs) are the most commonly employed techniques for diagnosing patients suspected of malaria in both public and private hospitals, with Plasmodium falciparum histidine-rich protein-2 (PfHRP2) antigen detection kits being the most widely used. Factors such as the deletion of the PfHRP2 gene in some Plasmodium falciparum strains, the prozone effect, the presence of other Plasmodium species, and the persistence of the PfHRP2 antigen in the blood circulation even after successful treatment contribute to false results from PfHRP2 antigen detection RDTs. Pan plasmodium lactate dehydrogenase (Pan pLDH) antigen detection kits can identify all the Plasmodium species and are not affected by either PfHRP2 gene deletion or prozone effects. This cross-sectional survey aimed to determine the effectiveness of PfHRP2 and PAN pLDH RDTs for malaria diagnosis in healthcare facilities in Katsina State. A total of 353 blood samples were collected from patients clinically suspected of malaria. Each sample was tested with Abbott PfHRP2 and Pan pLDH RDT kits to assess overall competency in malaria detection using two different antigen targets. All the samples were also screened for malaria parasites by microscopic examination. The results showed that PfHRP2 RDT has a slightly higher sensitivity and negative predictive value (NPV) of 98.2% and 99.2%, respectively, compared to Pan pLDH RDT (97.4% and 98.8%, respectively). Pan pLDH RDT, however, has an edge over PfHRP2 RDT in terms of specificity and positive predictive value (PPV), with 100% for both, while PfHRP2 had a specificity and PPV of 99.6% and 99.1%, respectively. Cohen’s Kappa showed perfect agreement between the RDTs and microscopy, with values of 0.97 and 0.98 for the Pan pLDH and PfHRP2 RDTs, respectively. The combined use of PfHRP2 and Pan-pLDH RDTs demonstrated superior diagnostic performance compared with either test used alone, achieving higher sensitivity, overall accuracy, and near-perfect agreement with microscopy.