ImmunoDOT is a dot-blot assay system combining microwell EIA and western blot advantages. Like microwell, a purified antigen set at a clinically meaningful cutoff is applied to nitrocellulose membrane. Reactivity is detected using the same reagent system used in most western blot assays. Extractable nuclear antigens (ENA) and chicken red blood cells nuclei compose the ANA dot and double-stranded DNA is separately and simultaneously measured. Additionally, if ENA reactivity is present, the test notes which type, RNP/Sm or SS-A/B. This test is accepted as an ANA sceening method.