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) demonstrate 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 not stare so long that you convince yourself to call it positive.
Negative:
- No discernible pattern in interphase cells
- Mitotics may be hard to find
- Do not confuse intensity with positivity
- Do not stare so long that you talk yourself into a positive
- Be consistent
