54004-7

LOINC code 54004-7 identifies "Human upstream binding factor Ab [Titer] in Serum by Immunofluorescence". This entity has two names: "nucleolar organizing region (NOR) 90" versus "human upstream binding factor (hUBF)". Both names are right, and the literature looking for the antibody in autoimmune patients almost uniformly includes both names and the historical context. NOR90 stuck because it was called that by the author of the original finding in autoimmune patients (Rodriguez-Sanchez, et al, 1987), but a few years later (1994), the antigen was found to be identical to already characterized hUBF. So we are stuck with the 2 names. hUBF is more technically specific, and at least one recent review calls it "anti-hUBF, formerly anti-NOR 90" (Journal of Dermatology 2010; 37: 42-53). So we will use that as its primary name.

This code measures Human upstream binding factor Ab in Ser. It belongs to the SERO class in the LOINC classification.

LOINC (Logical Observation Identifiers Names and Codes) is a universal standard for identifying laboratory and clinical observations. It is maintained by the Regenstrief Institute and used worldwide for health data exchange.