ʻO ka Vitamin D he huaʻaola a he hormone steroid hoʻi, ʻo ia hoʻi me VD2 a me VD3, nona ke ʻano like. Hoʻololi ʻia ka Vitamin D3 a me D2 i 25 hydroxyl vitamin D (me 25-dihydroxyl vitamin D3 a me D2). 25-(OH) VD i loko o ke kino kanaka, struction paʻa, kiʻekiʻe ka manaʻo. Hōʻike ka 25-(OH) VD i ka nui o ka huaora D , a me ka hiki ke hoʻololi i ka vitamina D, no laila ua manaʻo ʻia ʻo 25-(OH)VD ka hōʻailona maikaʻi loa no ka loiloi ʻana i ke kiʻekiʻe o ka vitamina D. Hoʻokumu ʻia ka Diagnostic Kit ma immunochromatography a hiki ke hāʻawi i kahi hopena i loko o 15 mau minuke.