Diversity in Enteric Fever Diagnostic Protocols and Recommendation for Composite Reference Standard

 Enteric fever causes serious health problem and brings about significant death and ill health globally because of the absence of decisive diagnostic techniques. The ability of frequently used assay to authenticate the absence of enteric fever is debatable. This research study aimed to appraise the specificity and sensitivity of typhoid diagnosis for establishing highly accurate diagnostic techniques and to recommend appropriate standardized composite reference.

 Published articles indexed in Google scholar, MEDLINE and PubMed were reviewed for hospital-based findings. Independent sample t-test was utilized to ascertain differences in mean percentage specificity and sensitivity.

From the 432 articles identified in this study, 53 were used in the analysis. The result outcome reveals that, Widal techniques show moderate accuracy with percentage average specificity (55%), sensitivity (53.8%), positive predictive value of 57.8% and negative predictive value of 55.6% in comparison to 28%, 29.4%,  29.5%, and 27.8% of Typhidot  respectively. 34.4% of the studies used prospective study design. The results revealed a statistically significant association in the sensitivity between Typhidot and Widal at p<0.05. The finding also presented emerging enteric fever diagnostic tests such as protein biomarkers, metabolite biomarkers, nucleic acid biomarkers and genomics. Antigens that were regularly assayed are lipopolysaccharides (LPS) and hemolysin E (HlyE).  Highest specificity of 96% and sensitivity of 96% was obtained in anti-LPS IgA.

 Based on the result outcome, it is recommended that, blood culture and Widal techniques having sensitivity of 60% and 53.8% respectively be used as a harmonized composite reference standard for enteric fever diagnosis to improve prevalence appraisals.