Dataset Information

Accuracy of a dual path platform (DPP) assay for the rapid point-of-care diagnosis of human leptospirosis.

ABSTRACT:

Background

Diagnosis of leptospirosis by the gold standard serologic assay, the microscopic agglutination test (MAT), requires paired sera and is not widely available. We developed a rapid assay using immunodominant Leptospira immunoglobulin-like (Lig) proteins in a Dual Path Platform (DPP). This study aimed to evaluate the assay's diagnostic performance in the setting of urban transmission.

Methodology

We determined test sensitivity using 446 acute and convalescent sera from MAT-confirmed case-patients with severe or mild leptospirosis in Brazil. We assessed test specificity using 677 sera from the following groups: healthy residents of a Brazilian slum with endemic transmission, febrile outpatients from the same slum, healthy blood donors, and patients with dengue, hepatitis A, and syphilis. Three operators independently interpreted visual results without knowing specimen status.

Results

The overall sensitivity for paired sera was 100% and 73% for severe and mild disease, respectively. In the acute phase, the assay achieved a sensitivity of 85% and 64% for severe and mild leptospirosis, respectively. Within seven days of illness onset, the assay achieved a sensitivity of 77% for severe disease and 60% for mild leptospirosis. Sensitivity of the DPP assay was similar to that for IgM-ELISA and increased with both duration of symptoms (chi-square regression P?=?0.002) and agglutinating titer (Spearman ??=?0.24, P<0.001). Specificity was ?93% for dengue, hepatitis A, syphilis, febrile outpatients, and blood donors, while it was 86% for healthy slum residents. Inter-operator agreement ranged from very good to excellent (kappa: 0.82-0.94) and test-to-test reproducibility was also high (kappa: 0.89).

Conclusions

The DPP assay performed acceptably well for diagnosis of severe acute clinical leptospirosis and can be easily implemented in hospitals and health posts where leptospirosis is a major public health problem. However, test accuracy may need improvement for mild disease and early stage leptospirosis, particularly in regions with high transmission.

SUBMITTER: Nabity SA

PROVIDER: S-EPMC3486890 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Publications

Accuracy of a dual path platform (DPP) assay for the rapid point-of-care diagnosis of human leptospirosis.

Nabity Scott A SA Ribeiro Guilherme S GS Aquino Carolina Lessa CL Takahashi Daniele D Damião Alcinéia Oliveira AO Gonçalves André H O AH Miranda-Filho Demócrito B DB Greenwald Rena R Esfandiari Javan J Lyashchenko Konstantin P KP Reis Mitermayer G MG Medeiros Marco A MA Ko Albert I AI

PLoS neglected tropical diseases 20121101 11

<h4>Background</h4>Diagnosis of leptospirosis by the gold standard serologic assay, the microscopic agglutination test (MAT), requires paired sera and is not widely available. We developed a rapid assay using immunodominant Leptospira immunoglobulin-like (Lig) proteins in a Dual Path Platform (DPP). This study aimed to evaluate the assay's diagnostic performance in the setting of urban transmission.<h4>Methodology</h4>We determined test sensitivity using 446 acute and convalescent sera from MAT- ...[more]

PMID: 23133686

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Project description:BackgroundTruenat is a novel molecular assay that rapidly detects tuberculosis (TB) and rifampicin-resistance. Due to the portability of its battery-powered testing platform, it may be valuable in peripheral healthcare settings in India.MethodsUsing a microsimulation model, we compared four TB diagnostic strategies for HIV-negative adults with presumptive TB: (1) sputum smear microscopy in designated microscopy centers (DMCs) (SSM); (2) Xpert MTB/RIF in DMCs (Xpert); (3) Truenat in DMCs (Truenat DMC); and (4) Truenat for point-of-care testing in primary healthcare facilities (Truenat POC). We projected life expectancy, costs, incremental cost-effectiveness ratios (ICERs), and 5-year budget impact of deploying Truenat POC in India's public sector. We defined a strategy "cost-effective" if its ICER was <US$990/year-of-life saved (YLS). Model inputs included: TB prevalence, 15% (among those not previously treated for TB) and 27% (among those previously treated for TB); sensitivity for TB detection, 89% (Xpert) and 86% (Truenat); per test cost, $12.63 (Xpert) and $13.20 (Truenat); and linkage-to-care after diagnosis, 84% (DMC) and 95% (POC). We varied these parameters in sensitivity analyses.ResultsCompared to SSM, Truenat POC increased life expectancy by 0.39 years and was cost-effective (ICER $210/YLS). Compared to Xpert, Truenat POC increased life expectancy by 0.08 years due to improved linkage-to-care and was cost-effective (ICER $120/YLS). In sensitivity analysis, the cost-effectiveness of Truenat POC, relative to Xpert, depended on the diagnostic sensitivity of Truenat and linkage-to-care with Truenat. Deploying Truenat POC instead of Xpert increased 5-year expenditures by $270 million, due mostly to treatment costs. Limitations of our study include uncertainty in Truenat's sensitivity for TB and not accounting for the "start-up" costs of implementing Truenat in the field.ConclusionsUsed at the point-of-care in India, Truenat for TB diagnosis should improve linkage-to-care, increase life expectancy, and be cost-effective compared with smear microscopy or Xpert.

Dataset Information

Accuracy of a dual path platform (DPP) assay for the rapid point-of-care diagnosis of human leptospirosis.

Background

Methodology

Results

Conclusions

Publications

Accuracy of a dual path platform (DPP) assay for the rapid point-of-care diagnosis of human leptospirosis.

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