Functional assays for C1 inhibitor (chromogenic or EIA) are expressed as the percentage of the mean level in normal specimens rather than as a mass concentration. The mass concentration of C1 inhibitor in a subject with low C1 inhibitor function may be low or normal depending on whether the patient has normal amounts of a dysfunctional protein.
4476-8 Complement Cl esterase inhibitor.functional [Mass/volume] in Serum or Plasma may be incorrect
2 Likes
Hello Bruce, it is great to hear from you! I would like to circulate this comment through the Lab LOINC committee list serve. Do you have a particular reagent manufacturer in mind for this measurement?
Be in touch soon; the committee is on summer hiatus until August.
Pam
1 Like
Hi Pam. Nice hearing from you as well. The 2 most widely used functional C1 inhibitor assays are the Quidel MicroVue™ C1-Inhibitor Plus EIA and the Technoclone TECHNOCHROM® C1-INH chromogenic assay. Both report results as a %age of a normal population. I am not aware of any functional C1 inhibitor assay that is reporting results as a mass concentration. We are about to switch from the chromogenic assay to the EIA and need to remap to LOINC which is when I noticed this apparant issue. Please let mne know how I can participate.
1 Like