Blood or discharge found on the sidewall can serve as a source of material for PCR testing. In this video, a bloody discharge collected from the sidewall is transferred and used to make an imprint on an FTA® card.

Only a thin smear of mucus or bloody discharge is required. FTA® cards are designed to lyse cells and bind nucleic acids efficiently, so even a minimal amount of material contains more than enough viral DNA for PCR detection of ILT.

A good rule of thumb:
Just enough to lightly wet the surface of the circle
No visible “blob” or thick layer
A translucent or lightly coloured stain is ideal
Applying too much material can actually be counterproductive, because:
Excess mucus may inhibit PCR if not fully dried.
Thick layers dry slowly and may trap moisture, reducing sample stability.
Overloading the card can make punching difficult for the laboratory.

Because ILT lesions shed abundant epithelial cells and viral particles, even a very small imprint is typically sufficient for detecting Gallid alphaherpesvirus‑1 during the acute phase.