Virus testing: What does this result mean?

[BrassavolaStars]

Hello all,

I’ve been testing my plants since I found a virus. I tested a blooming cattleya (no color-break) that has strange leaf spots on the older leaves.

I have a red control line and two gray colorless lines that are still visible though as they are slightly grayer than the strip. I assume this counts as a negative? Is that correct? I used older leaves for the sample.