He huaora te Huaora D, ā, he homoni steroid anō hoki, ko te nuinga kei roto ko te VD2 me te VD3, ā, he tino ōrite te hanganga. Ka hurihia te Huaora D3 me te D2 ki te 25 hydroxyl huaora D (tae atu ki te 25-dihydroxyl huaora D3 me te D2). He 25-(OH) VD i roto i te tinana tangata, he hanganga pumau, he kukū teitei. Ko te 25-(OH) VD e whakaata ana i te nui katoa o te huaora D, me te kaha hurihanga o te huaora D, nō reira e kiia ana ko te 25-(OH) VD te tohu pai rawa atu mō te aromatawai i te taumata o te huaora D. Ko te Kete Tātaritanga e hangai ana ki te immunochromatography, ā, ka taea te whakaputa hua i roto i te 15 meneti.