On the right is an example of a negative sample. An indirect immunofluorescence (IFA) method was used in the top image and the Colorzyme® method was used in the bottom image. The sample represents a difficult, borderline sample and is intended to illustrate the most difficult type of negative sample. (Samples that are clearly negative are easy to interpret and are hard to photograph.)
Notice there is no clearly discernible pattern in the interphase cells (a).
The metaphase mitotic cells (b) are demonstrating some weak staining, but without a clearly discernible pattern in the interphase cells, the sample is ANA negative.
When encountering borderline samples like the ones in these photos, remember to use less magnification (200x total) and do not stare so long that you convince yourself into calling it positive.
- No discernible pattern in interphase cells
- Mitotics may be hard to find
- Do not confuse intensity with positive
- Do not stare so long you talk yourself into a positive
- Be consistent