Diagnostic capacity, and predictive values of rapid diagnostic tests for accurate diagnosis of Plasmodium falciparum in febrile children in Asante-Akim, Ghana

Abstract

BackgroundThis study seeks to compare the performance of HRP2 (First Response) and pLDH/HRP2 (Combo) RDTs for falciparum malaria against microscopy and PCR in acutely ill febrile children at presentation and follow-up.MethodsThis is an interventional study that recruited children < 5 years who reported to health facilities with a history of fever within the past 72 h or a documented axillary temperature of 37.5 °C. Using a longitudinal approach, recruitment and follow-up of participants was done between January and May 2012. Based on results of HRP2-RDT screening, the children were grouped into one of the following three categories: (1) tested positive for malaria using RDT and received anti-malarial treatment (group 1, n = 85); (2) tested negative for malaria using RDT and were given anti-malarial treatment by the admitting physician (group 2, n = 74); or, (3) tested negative for malaria using RDT and did not receive any anti-malarial treatment (group 3, n = 101). Independent microscopy, PCR and Combo-RDT tests were done for each sample on day 0 and all follow-up days.ResultsMean age of the study participants was 22 months and females accounted for nearly 50%. At the time of diagnosis, the mean body temperature was 37.9 °C (range 35–40.1 °C). Microscopic parasite density ranged between 300 and 99,500 parasites/µL. With microscopy as gold standard, the sensitivity of HRP2 and Combo-RDTs were 95.1 and 96.3%, respectively. The sensitivities, specificities and predictive values for RDTs were relatively higher in microscopy-defined malaria cases than in PCR positive-defined cases. On day 0, participants who initially tested negative for HRP2 were positive by microscopy (n = 2), Combo (n = 1) and PCR (n = 17). On days 1 and 2, five of the children in this group (initially HRP2-negative) tested positive by PCR alone. On day 28, four patients who were originally HRP2-negative tested positive for microscopy (n = 2), Combo (n = 2) and PCR (n = 4).ConclusionThe HRP2/pLDH RDTs showed comparable diagnostic accuracy in children presenting with an acute febrile illness to health facilities in a hard-to-reach rural area in Ghana. Nevertheless, discordant results recorded on day 0 and follow-up visits using the recommended RDTs means improved malaria diagnostic capability in malaria-endemic regions is necessary.

Malaria parasitaemia and mRDT diagnostic performances among symptomatic individuals in selected health care facilities across Ghana

“…With regards to diagnostic accuracy using microscopy as standard, CareStart™ Malaria HRP2 (Pf) kit showed over 90.0% SEN and NPV in all the regions of the country, which compares well with previous studies showing 95.1–98.2% SEN and 95.8–97.7% NPV in parts of the country [ 23 , 24 ]. Since mRDT is mainly used for diagnosis and not screening, the high SEN and NPV observed in this study suggests that CareStart™ Malaria HRP2 (Pf) kit used routinely in the country is playing a significant role in the proper management of suspected uncomplicated malaria cases [ 25 , 26 ].…”

High value of rapid diagnostic tests to diagnose malaria within children: A systematic review and meta-analysis

“…Since HRP2 will be cleared slowly from bloodstream if the treatment of P. falciparum is successful and it can contribute to a higher false-positive rate of RDTs [27], our analyses were grouped into two parts according to the usage time of RDTs (before or after ACT treatment). There were 9 studies that adopted multiple types of RDTs and/or reference standards: 6 studies evaluated 2 types of RDTs [28][29][30][31][32][33], 2 studies evaluated 3 types of RDTs [18,34], and 2 studies selected two different types of reference standards [32,35]. Particularly, in one study, two staffs read the RDTs strips respectively, so there were two different results for each type of RDTs [29].…”

Plasmodium falciparum Histidine-Rich Protein 2 and 3 Gene Deletions in Strains from Nigeria, Sudan, and South Sudan

“…The sample sizes are insufficient to comment on regional proportions. Baselines for these regions are undetermined, although a low level of false-negative results using HRP2-based RDTs has been reported in rural Ghana ( 34 ), and varying levels (0%–30%) of pfhrp2 deletion have been observed in regions of Kenya ( 12 ). pfhrp2/pfhrp3 double - deleted parasites have been observed within the China–Myanmar border area, where baseline pfhrp2 -deleted parasite proportions were as low as 4% ( 17 ).…”