These images are provided as examples of what are considered as ANA-negative as viewed under a microscope. Since a negative ANA can be represented by a number of different images, it should be clear that AC-0 should not be regarded as the definite example but used for comparison purposes only. The guiding feature that links these variable possibilities is the absence of a clear-cut staining in any given subcellular structure. This definition is both subjective and semi-quantitative at best.

There should be a discussion regarding how ANA-positive vs ANA-negative cut-off is determined. There are general consensus that such cut-offs should be determined experimentally and locally with normal population controls. The cut-off is highly dependent on the HEp-2 substrates used by individual laboratories, including factors specific to HEp-2 slide manufacturers and lot-to-lot variations, fluorochrome conjugated secondary antibody reagents, microscope and camera settings, serum dilutions, and other variables.

In viewing these AC-0 images online using a computer screen, note that the screen default brightness setting may vary from computer to computer and some adjustment may be necessary for appropriate interpretation. For computer with two screens, the brightness for both screen is not necessary in sync either. These AC-0 images are selected to show some definition of cells, including cells in metaphase. If one cannot see sufficient details, probably the screen brightness is set too dark. On the other hand, if these images show too much green staining, please consider the screen brightness is set too bright. In summary, viewers of these images on computer screen should make appropriate adjustment in their screen brightness setting accordingly.

Please note that when these AC-0 images are downloaded and viewing with PC/Mac computers, there may be additional variations depending on the image viewing software, in addition to screen brightness setting as discussed above.

See Herold et al. for full discussion (Clin Chem Lab Med. 2018;56:1799-802.)

Herold M, Klotz W, Andrade LEC, Conrad K, de Melo Cruvinel W, Damoiseaux J, Fritzler MJ, von Muhlen CA, Satoh M, Chan EKL. International Consensus on Antinuclear Antibody Patterns: defining negative results and reporting unidentified patterns. Clin Chem Lab Med. 2018;56:1799-802.