Computational protocol: Diagnostic accuracy of the InBiOS AMD rapid diagnostic test for the detection of Burkholderia pseudomallei antigen in grown blood culture broth

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Protocol publication

[…] A positive, valid test result was indicated by the appearance of both a control and test line (Fig. a). A negative, valid test result was indicated by the sole presence of a control line (Fig. b). In absence of a control line, the test was defined as invalid. Test line intensities were scored as “faint” (hardly visible) and “weak,” “medium,” or “strong” if the test line intensity was respectively weaker, equal, or stronger compared to the control line []. In addition, the strip background at the moment of reading was scored and recorded as “light” (optimal clearance), “medium” (background present but control line clearly visible), and “high” (background present, control line not clearly visible). In case of false-positive or false-negative results, the laboratory logbook was assessed to exclude clerical errors, the blood culture broth was inoculated onto sheep blood agar and incubated for 48 h, and the corresponding isolate was retrieved from storage and re-identified by standard biochemical methods. If this resulted in an identification different from the one recorded in the SHCH blood culture logbook, or if no isolate could be retrieved from the broth, the sample was excluded from subsequent analysis since the presence of B. pseudomallei in the blood culture broth sample could not be proven. [...] All results were first recorded on a paper form and afterwards transcribed into an electronic database (Microsoft Excel, Supplementary Table ). Only the principal investigator and staff reading and recording the test results had access to this database. Sensitivity and specificity of the InBiOS AMD RDT compared to the identification of the blood culture isolate as the reference method test were calculated with 95% confidence intervals (CI) and expressed as consensus results at the first testing (results of repeatability testing were not considered). Inter-observer agreements for test line intensities and positive and negative test results were expressed by the percentage of overall agreement and by Kappa values. A Kappa value of 0.6–0.8 was considered good, and > 0.8 was considered excellent []. Differences in proportions were assessed using chi-square analysis. When the sample size was too small or when dependent samples were compared, respectively, Fisher exact tests or McNemar tests were used. The statistical analysis was performed with GraphPad software (www.graphpad.com) and Vassarstats (www.vassarstats.net). The clearance of the test background was expressed as the proportion of samples with light, medium, and high background, observed by the first reader. All data generated or analyzed during this study are included in this published article and its . […]

Pipeline specifications

Software tools Laboratory Logbook, VassarStats
Application Miscellaneous
Organisms Burkholderia pseudomallei, Homo sapiens, Burkholderia cepacia