Evaluation of Rapid Diagnostic Tests for Early Diagnosis of Malaria in Rural India to Prevent Deadly Complications

BACKGROUND As per World Malaria Report, 2018, There were an estimated 219 million cases and 435000 related deaths in 2017, with about 9.5 million malaria cases and 16,733 related deaths in 2017 in India. The most severe clinical form of malaria is caused by P. falciparum infection. The disease is usually fatal in non-immunes. The complications of falciparum malaria are cerebral malaria, pulmonary oedema, septicaemia and shock. If these complications are not diagnosed early and are not treated adequately, the patient becomes fatal. To prevent these complications, we need early diagnosis. Clinical diagnosis of malaria requires microscopic detection of the parasite. Diagnosis of malaria by microscopy is the gold standard but requires expertise and is time consuming. Recently, new rapid malaria detection tests based on detection of an enzyme produced by live parasites, parasite lactate dehydrogenase (pLDH) and Histidine Rich Proteins (HRPII) have been developed. It is simple, easy to use and does not require expertise. In the present study, the Rapid Diagnostic Tests are evaluated for the effectiveness for early diagnosis of Malaria in Rural India to prevent deadly complications. METHODS The study, conducted in a hospital, included 733 patients with fever of 3 days duration after obtaining consent from the subjects and approval from the ethical committee. 733 whole blood samples were collected and tested for Smear Microscopy for Malarial parasites and were also tested with Rapid Diagnostic Tests. The study was spread over 10 months from June, 2018 to March, 2019 and results were sent for analysis. Rapid Diagnostic Test (RDT) was compared with 'Gold Standard' technique i.e.; Microscopy- Smear Examination with the help of X-2 values, sensitivity, specificity, positive predictive values, negative predictive values, percentage of false negatives, percentage of false positives, positive likelihood ratio (LR+), and negative likelihood ratio (LR-) values. RESULTS The results of Rapid Diagnostic Test (RDT) were compared with smear microscopy and it was found that RDT is as effective as Smear Microscopy in diagnosing Malaria with 97.81% sensitivity, 97.82% specificity, 97.20% Positive predictive value and 98.30% Negative predictive value. In diagnosing the species of Malaria also, RDT is found to be as effective as Smear Microscopy in differentiating Falciparum Malaria with 97.98% sensitivity value, 98.79% specificity value, 97.49% positive predictive value, 99.03% negative predictive value. RDT is found to be as effective as Smear Microscopy in differentiating Vivax Malaria with 97.54% sensitivity, 99.03% specificity, 96.75% positive predictive value and 99.27% negative predictive value. CONCLUSIONS The present study concludes Rapid Diagnostic Tests are effective screening tests as shown by the high sensitivity, specificity and predictive values, high Likelihood positive(LR+) and low Likelihood Negative(LR-) values.