Could you have gingivitis if your gums don't bleed when you brush and floss?

Yes: Red and swollen gum tissues also could indicate gingivitis.

Unlikely: Gingivitis is an inflammation of the gingiva (gums). When something is inflamed it typically bleeds very easily. Therefore, in most cases people with gingivitis will have gum that bleed easily.

Rare, but maybe...: By definition, gingivitis is a condition of inflamed gum. Inflamed gum must bleed when brush or floss, unless it is severely fibroses in heavy smoking individual. However, you may have bone loss and the gum does not bleed (as in the case of ljp). Periodontitis is a condition of loss of periodontal attachment, i.E, alveolar bone, periodontal ligament, cementum.

No: If you don't have bleeding when brushing and flossing, then you can't have gingivitis. Gingivitis is inflammation of the gingiva, which means increased numbers of blood vessels which are easily damaged, resulting in bleeding. If there is no bleeding, no inflammation, thus no gingivitis.