Diagnostic Test Kits for Dengue Virus Detection Evaluated

Laboratory diagnosis of dengue with a single serum specimen obtained during the acute phase of the illness requires tests to detect immunoglobulin M (IgM) antibodies to Dengue virus or the virus genome.

Commercially available diagnostic test kits for detection of the Dengue virus (DENV) non-structural protein 1 (NS1) and anti-DENV IgM have been evaluated for their sensitivity and specificity and other performance characteristics.

An international team of scientists led by those at the [US] Centers for Disease Control and Prevention (CDC; San Juan, Puerto Rico) examined newly available commercial tests that detect the virus protein NS1, as well as new tests for IgM anti-DENV in microplate or rapid diagnostic test (RDT) formats. This analytic study used specimens from laboratory confirmed dengue patients worldwide, which makes the results widely generalizable.

A DENV NS1 panel cconsisted of a total of 390 dengue patient serum specimens in three sub-panels: 192 dengue patients who were DENV positive by virus isolation and/or polymerase chain reaction (PCR) for DENV ribonucleic acid (RNA), 146 DENV RNA or culture negatives, and 52 challenge specimens from other illnesses or conditions. An anti-DENV IgM panel consisted of three subpanels with 527 patient serum specimens: 228 anti-DENV IgM positive paired specimens from patients with dengue and 155 DENV IgM negative and 144 challenge specimens. All specimens were tested by the solid-phase anti-DENV IgM Antibody Capture Enzyme Linked Immunosorbent Assay (IgM MAC-ELISA).

The DENV kits from seven different manufacturers were tested. The results were analyzed to determine sensitivity, specificity, inter-laboratory and inter-reader agreement, lot-to-lot variation and ease-of-use. NS1 ELISA sensitivity was 60% to 75% and specificity 71% to 80%; NS1 RDT sensitivity was 38% to 71% and specificity 76% to 80%; the IgM anti-DENV RDTs sensitivity was 30% to 96%, with a specificity of 86% to 92%, and IgM anti-DENV ELISA sensitivity was 96% to 98% and specificity 78% to 91%.

The authors concluded that NS1 tests were generally more sensitive in specimens from the acute phase of dengue and in primary DENV infection, whereas IgM anti-DENV tests were less sensitive in secondary DENV infections. The reproducibility of the NS1 RDTs ranged from 92% to 99% and the IgM anti-DENV RDTs from 88% to 94%.The study was published on October 16, 2014, in the journal Public Library of Science Neglected Tropical Diseases.

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