Diagnostic Efficacy of Microscopy, Rapid Diagnostic Test and Polymerase Chain Reaction for Malaria Using Bayesian Latent Class Analysis

• Published in: Indian journal of medical microbiology Vol. 35; no. 3; pp. 376 - 380
• Main Authors: Saha, Sreemanti, Narang, Rahul, Deshmukh, Pradeep, Pote, Kiran, Anvikar, Anup, Narang, Pratibha
• Format: Journal Article
• Language: English
• Published: India Elsevier B.V 01.07.2017; Elsevier Limited
• Subjects: Adolescent; Adult; Aged; Bayes Theorem; Bayesian analysis; Bayesian latent class analysis; Child; Confidence intervals; Cross-Sectional Studies; Deoxyribonucleic acid; Diagnostic systems; Diagnostic tests; Diagnostic Tests, Routine - methods; DNA; DNA polymerase; evaluation; Female; Hospitals; Humans; Immunoassay - methods; Infections; Infectious Disease; Latent class analysis; Malaria; Malaria - diagnosis; Male; Microscopy; Microscopy - methods; Middle Aged; Parasites; Plasmodium; Plasmodium falciparum; Plasmodium vivax; Polymerase chain reaction; Polymerase Chain Reaction - methods; rapid diagnostic test; Sensitivity; Sensitivity and Specificity; Smear; Tertiary Care Centers; Vector-borne diseases; Vectors (Biology); Young Adult; evaluation; microscopy; rapid diagnostic test; malaria; Bayesian latent class analysis; polymerase chain reaction
• ISSN: 0255-0857; 1998-3646
• DOI: 10.4103/ijmm.IJMM_17_199

Introduction: The diagnostic techniques for malaria are undergoing a change depending on the availability of newer diagnostics and annual parasite index of infection in a particular area. At the country level, guidelines are available for selection of diagnostic tests; however, at the local level, this decision is made based on malaria situation in the area. The tests are evaluated against the gold standard, and if that standard has limitations, it becomes difficult to compare other available tests. Bayesian latent class analysis computes its internal standard rather than using the conventional gold standard and helps comparison of various tests including the conventional gold standard. Materials and Methods: In a cross-sectional study conducted in a tertiary care hospital setting, we have evaluated smear microscopy, rapid diagnostic test (RDT), and polymerase chain reaction (PCR) for diagnosis of malaria using Bayesian latent class analysis. Results: We found the magnitude of malaria to be 17.7% (95% confidence interval: 12.5%–23.9%) among the study subjects. In the present study, the sensitivity of microscopy was 63%, but it had very high specificity (99.4%). Sensitivity and specificity of RDT and PCR were high with RDT having a marginally higher sensitivity (94% vs. 90%) and specificity (99% vs. 95%). On comparison of likelihood ratios (LRs), RDT had the highest LR for positive test result (175) and the lowest LR for negative test result (0.058) among the three tests. Conclusion: In settings like ours conventional smear microscopy may be replaced with RDT and as we move toward elimination and facilities become available PCR may be roped into detect cases with lower parasitaemia.