Vidas

VIDAS
Vitek Immuno Diagnostic Assay System

VIDAS principle
• Based on specific antibody and antigen reaction • Antigen = pathogen or its components in the sample
See notes

VIDAS substrate • One of the antibodies used has an enzyme covalently linked to it
⇒antibody-enzyme conjugate

Colored product or light antibodyenzyme conjugate

• Antigen detected by enzyme assay
– Substrate added is converted to a colored or fluorescent product

antigen

Components of VIDAS System
• reagent strip • solid phase receptacles (SPRs) • fluorescence optical system • automatic pipetting system

Solid phase receptacle (SPR)

Reagent Strip
• 1 sample well • 8 reagent wells
– washing solutions – enzyme conjugated antibody – enzyme substrate Single reagent strip

• 1 cuvette • covered with a foil seal

Dual reagent strip (with reference)

See notes, p.2

VIDAS Steps and Principle
1. Sample is pipetted in and out of SPR
⇒ target organism binds to antibody (1st) on the inside of SPR

VIDAS Steps and Principle (cont.)
2. Washing buffer is pipetted in and out of SPR
⇒ unbound or nonspecifically bound sample is removed

VIDAS Steps and Principle (cont.)
3. Enzyme conjugated antibody (2nd) specific for target organism is pipetted in and out of SR
⇒ 2nd antibody binds to organism captured previously by the 1st antibody

VIDAS Steps and Principle (cont.)
4. Washing buffer is pipetted in and out of SPR
⇒ unbound or non-specifically bound 2nd antibody is removed

VIDAS Steps and Principle (cont.)
5. Enzyme substrate is pipetted in and out of the SPR
⇒ substrate is broken down by enzyme on the 2nd antibody to form a fluorescent product
Antibody enzyme conjugate

Substrate

VIDAS Steps and Principle (cont.)
6. Reaction product is pipetted into the cuvette and the fluorescence read

VIDAS system
See lab sheet • Must be calibrated prior to use of each lot of kit
– A standard is provided with the kit for the calibration –