Performance of rapid diagnostic test, blood-film microscopy and PCR for the diagnosis of malaria infection among febrile children from Korogwe District, Tanzania

Abstract

Background: Rapid diagnostic tests (RDT) and light microscopy are still recommended for diagnosis to guide the clinical management of malaria despite difficult challenges in rural settings. The performance of these tests may be affected by several factors, including malaria prevalence and intensity of transmission. The study evaluated the diagnostic performance of malaria RDT, light microscopy and polymerase chain reaction (PCR) in detecting malaria infections among febrile children at outpatient clinic in Korogwe District, northeastern Tanzania. Methods:The study enrolled children aged 2-59 months with fever and/or history of fever in the previous 48 h attending outpatient clinics. Blood samples were collected for identification of Plasmodium falciparum infection using histidine-rich-protein-2 (HRP-2)-based malaria RDT, light microscopy and conventional PCR.Results: A total of 867 febrile patients were enrolled into the study. Malaria-positive samples were 85/867 (9.8 %, 95 % CI, 7.9-12.0 %) by RDT, 72/867 (8.3 %, 95 % CI, 6.5-10.1 %) by microscopy and 79/677 (11.7 %, 95 % CI, 9.3-14.3 %) by PCR. The performance of malaria RDT compared with microscopy results had sensitivity and positive predictive value (PPV) of 88.9 % (95 % CI, 79.3-95.1 %) and 75.3 % (95 % CI, 64.8-84.0 %), respectively. Confirmation of P. falciparum infection with PCR analysis provided lower sensitivity and PPV of 88.6 % (95 % CI, 79.5-94.7 %) and 84.3 % (95 % CI, for RDT compared to microscopy. Conclusion:Diagnosis of malaria infection is still a challenge due to variation in results among diagnostic methods. HRP-2 malaria RDT and microscopy were less sensitive than PCR. Diagnostic tools with high sensitivity are required in areas of low malaria transmission.

Molecular investigation of sub-microscopic and mixed Plasmodium species infection in North-Central Nigeria

“…In a systematic review, Okell et al [18] also found that older age groups were generally associated with increased sub-microscopic carriages. Our results are in tandem agreement with previous studies showing that molecular detection techniques have greater sensitivity and specificity than either microscopy for the identification of single and mixed species infections [23,[39][40][41][42], as well as sub-microscopic infections [11,43]. The detection of Plasmodium parasites at very low density parasitaemia is difficult by microscopy and thus requires a molecular approach especially for surveillance or epidemiological studies [44].…”

Comparison of the diagnostic performance of microscopic examination with nested polymerase chain reaction for optimum malaria diagnosis in Upper Myanmar

“…The role of microscopic examination as the gold standard for malaria diagnosis has been questioned due to false negative results at low parasitaemiae levels (less than 20–30 parasites/μl of blood) and frequent errors in species identification in mixed infections [33]. The low diagnosis reliability of microscopy for species-specific and mixed-infections in endemic areas has been reported previously [12, 34–39]. Consistent with these previous reports, mixed infections that were missed in the microscopic examination were identified in 27 samples by molecular detection method.…”

Plasmodium malariae in the Colombian Amazon region: you don’t diagnose what you don’t suspect

“…However, reports of cross-reactivity and less-than-desirable performances regarding mixed infections hinder its potential and, therefore, it has been considered inferior to microscopy in such scenarios [12, 13]. According to some studies, HRP-2 malaria RDT and microscopy have been less sensitive than PCR and especially show limited detection thresholds in situations with low parasitaemia [14–16]. Microscopy and RDTs cannot reliably detect low-density infections [17].…”