Rapid diagnostic tests for typhoid and paratyphoid (enteric) fever

Area of Science:

• Clinical diagnostics
• Infectious diseases
• Public health

Background:

• Diagnosing typhoid (Salmonella Typhi) and paratyphoid (Salmonella Paratyphi A) in endemic areas is challenging.
• Commercial rapid diagnostic tests (RDTs) exist as alternatives to blood culture and the Widal test.
• The diagnostic accuracy of these RDTs for enteric fever is not clearly established.

Purpose of the Study:

• To assess the diagnostic accuracy of commercially available RDTs and prototypes for Salmonella Typhi or Paratyphi A.
• To evaluate RDT performance in symptomatic individuals residing in areas endemic for enteric fever.

Main Methods:

• A systematic search of multiple databases and registries was conducted up to March 2016.
• Diagnostic accuracy studies of enteric fever RDTs in symptomatic individuals from endemic areas were included.
• Reference standards were classified as Grade 1 (blood and bone marrow culture) or Grade 2 (blood culture-based methods).

Main Results:

• Thirty-seven studies involving 5080 participants evaluated 16 different RDTs.
• Meta-analyses showed moderate average sensitivity and specificity for TUBEX, Typhidot, and Test-It Typhoid (KIT) RDTs.
• No significant difference in diagnostic accuracy was found between the three main RDTs evaluated.

Conclusions:

• Few studies evaluating enteric fever RDTs had a low risk of bias.
• The three main RDTs demonstrated moderate diagnostic accuracy.
• More rigorous evaluations of alternative RDTs for enteric fever are necessary.