RAMP System Operations

A RAMP^® assay can be designed for one of two traditional immunoassay modes depending on the target analyte. Sandwich assays are used for analytes with a high molecular weight (such as cardiac markers), while inhibition assays are used for analytes with a low molecular weight (such as hormones and therapeutic drugs).
 
To perform a test, the analyzer is turned on. It automatically prompts the operator to enter a sample identification number and the operator identification number. The operator places a whole blood sample into the well of a Test Cartridge specific to the analyte of interest, and inserts the Test Cartridge into the analyzer. Once the Test Cartridge has been inserted no further intervention by the operator is required. A bar code on the bottom of the Test Cartridge is read by the analyzer prompting test-specific information, including the identity of the analyte being tested, lot number, and calibration details to be available for the determination of the amount of analyte in the sample.
 
Once added to the Test Cartridge, the solution permeates the membrane strip; moves through the Detection and Internal Standard Zones; and is ultimately analyzed by the flourescence reader.
 
The operational sequence of a RAMP sandwich assay is as follows:
 

 
A sample is applied into the sample well of the Test Cartridge and as it migrates along the strip, fluorescent-dyed latex particles coated with antigen-specific antibodies bind to antigen if present in the sample. The fluid sample, along with bound latex particles and unbound latex particles, is then transported by capillary action through the strip to the Detection and Internal Standard Zones.
 

 
The Detection Zone contains a second antibody specific to the target analyte. If the fluid sample contains the target analyte, it will be captured by the antibody in the Detection Zone, arresting the migration of the attached latex particles. If no target analyte is present, the latex particles will migrate past the Detection Zone. The concentration of analyte located at the Detection Zone is directly related to the concentration of target analyte in the sample. Past the Detection Zone is the Internal Standard Zone, which, for some sandwich assays, contains anti-mouse immunoglobulin. The Internal Standard particles bind and are arrested at this Zone.