A Novel Urine Method for the Diagnosis of Active Tuberculosis by Immunoassay for the Detection of ESAT-6 Using Hydrogel Nanoparticles in HIV Patients

Background: In patients with HIV, conventional tests are of low sensitivity; therefore, a new diagnostic test hydrogel nanoparticles reactive blue dye is proposed, which allows the capture, conservation and concentration ESAT-6 in urine. NIPAs copolymers that capture molecular weight proteins and protect against enzymatic degradation. Using an immunoassay, it is possible to detect quantify present in urine as a marker active TB. Design/Methods: Study Lima, Peru, HIV+ participants, ≥18 years without tuberculosis (TB). Smear microscopy, culture solid medium immunoassay were performed. The reference was diagnosis TB by radiological or clinical microbiological criteria (indication for treatment). There were 2 preanalytical processes: untreated treated (centrifuged, heated), then incubation NIPAm. After washing, elution, sonication, heat and centrifugation, final eluate obtained. This placed on nitrocellulose membranes, means fixation processes with anti-ESAT-6 anti-IgG antibodies, revelation C-DiGit&reg Blot Scanner FluorChem R FR0001. Calibration curves included the membranes, density measured using Image J software. ROC curves, sensitivity and specificity Results: result by groups patient: ROC: 0.75, cut-off point ≥24.06 ng/ml, sensitivity 76.32%, 68.89%, ≤200 cells CD4 mm3/ml, 0.78, cutoff point ≥26.20 sensitivity 75.86%, 71.88%, >200 CD4 mm3 cells/ml, 0.73, cutoff ≥24.6 CD4 73.68%, specificity 73.68%. Conclusions: detection assay NIPAm effective, higher rates CD4 cells/mm3, being more sensitive than smear and culture, but less specific.