The VivaDiagTM SARS-CoV-2 Ag FIA test is a rapid assay for the qualitative detection of SARS-CoV-2 nucleocapsid protein antigen in human nasal, oropharyngeal and nasopharyngeal swab specimens. The test is an in vitro diagnostic and for professional use only. It is intended for use in clinical laboratories and should be used by health care professionals at health care facilities. It is not intended for self-testing. The VivaDiagTM SARS-CoV-2 Ag FIA test is based on fluorescence immunochromatography technology. Each test consists of a monoclonal anti-SARS-CoV-2 antibody detector band (T-band) and a second polyclonal rat IgG antibody detector band (C-band).
The last generation tests seem to show results superimposable to RT-PCR assays (AMCLI Associazione Microbiologi Clinici Italiani Prot 01 -2021 "AMCLI operative indications on frequent questions related to molecular diagnosis of SARS-CoV infection"). - – Ministry of Health Circular
VivaDiag SARS-CoV-2 Ag FIA, principle and intended use
Once the sample has been collected and placed in the well of the device, it will react with the labelled antibody to form a complex that will move up the membrane by capillary action and bind to the labelled monoclonal anti-SARS cov-2 antibody with which the detection band is coated. If the sample contains SARS-COV-2 antigen, the previously fluorescently labelled complex will move up the membrane, bind to the SARS-CoV-2 antibody and fluoresce, the intensity of which is translated by the instrument (POCT VIM1000 analyser) into positive, negative or invalid results. The Vivadiag analyser is able to provide results that would not be visible to the naked eye.
Each kit contains: test device, chip code, sealed bottles (already filled with 300 L of reagent solution), test tubes, dispensers, test tube holder, sterile swabs and instruction leaflet.
Materials needed that may not be provided:
- VivaDiagTM POCT VIM1000 analyser
Clinical Performance of the FIA Ag Sars-Cov-2 Test
Limit of Detection (LOD)
The LOD for the VivaDiagTM SARS-CoV-2 Ag FIA assay was established using dilutions of an inactive viral culture. The material was supplied at a concentration of 8.65 x 106 TCID50/mL. Studies were designed to estimate the LOD of the assay using nasal swab samples, the starting material was added to a volume of human nasal matrix obtained from healthy donors confirmed negative for SARS-CoV-2.
|SARS-CoV-2 Titration||8.65 x106 TCID50 /mL|
|Dilution||1/10||1/100||1/1000||1/2000||1/ 4000||1/ 8000||1/ 16000||1/ 32000||1/ 64000||1/ 128000|
|Tested dilution concentration. (TCID50/mL)||8.65 x|
|Detection rate of 5 replicates||100% (5/5)||100% (5/5)||100% (5/5)||100% (5/5)||100% (5/5)||100% (5/5)||100% (5/5)||100% (5/5)||100% (5/5)||100% (4/5)|
|Detection rate of 20 replicates close to the cut-off (limit value)||NA||NA||NA||NA||NA||NA||NA||100% (20/20)||95% (19/20)||75% (15/20)|
|Uniform minimum positive concentration per analyte.||1.35 x102 TCID50 /mL|
|LOD (for inactive viral culture).||1.35 x102 TCID50 /mL|
Clinical Sensitivity and Specificity
A total of 156 specimens were tested using the VivaDiagTM SARS-CoV-2 Ag FIA assay. These samples were obtained by nasal swabs from symptomatic patients. The performance of the VivaDiagTM SARS-CoV-2 Ag FIA assay was compared to a commercial molecular test.
|VivaDiagTM SARS-CoV-2 Ag FIA Test with VIM2000||PCR|
|Sensitivity||96.97%(64/66, 95%CI, 89.61%~99.17%)|
|Specificity||100% (431/431, 95%CI, 99.12%~100%)|
|Accuracy||99.60% (495/497, 95%CI, 98.54%~99.89%)|