After the specimen has been collected according to the instructions and mixed with the Sample Buffer, the specimen/Sample Buffer mixture is absorbed into the absorbent pad at the end of the Test Strip. The liquid mixture continues to migrate up the Test Strip by a wicking action, until it encounters a dehydrated reagent conjugate which is rehydrated by the liquid. The reagent turns reddish-purple in color which is used later in the Test Strip to visualize the results. Specific proteins will bind to both positive (if any) and negative antibodies that may be present in the liquid containing the specimen.
The liquid continues to wick up the strip onto a nitrocellulose membrane. Once the liquid starts to appear on the membrane, the user will see a reddish-purple cloud migrate up the strip with the liquid. The liquid will continue to be drawn up to the top of the strip until the reddish-purple cloud on the membrane has cleared 20 minutes after the start of the test.
As the liquid containing antibodies bound to the conjugate crosses the membrane, it encounters the invisible reagent lines where the results are read.
The color intensity of the lines does not necessarily correlate to the amount of antibody captured or to the severity of the infection, if present. The results of the test are interpreted in the time frame noted in the product insert after adding the Test Strip to the Sample Buffer containing the specimen. At this time, the antibodies in the specimen will have had adequate time to migrate up the entire strip. A reddish-purple line will form indicative of the presence of antibodies, the test has been performed correctly, and/or the specimen is one with a recent or long term infection.