I-Vitamin D yivithamin kwaye ikwayi-hormone ye-steroid, ingakumbi i-VD2 kunye ne-VD3, umyalelo wayo ufana kakhulu.I-Vitamin D3 kunye ne-D2 iguqulelwe kwi-25 i-hydroxyl i-vitamin D (kuquka i-25-dihydroxyl i-vitamin D3 kunye ne-D2).I-25-(OH) i-VD emzimbeni womntu, umyalelo ozinzileyo, ukugxila okuphezulu.I-25-(OH) i-VD ibonisa inani elipheleleyo levithamini D, kunye nokukwazi ukuguqulwa kwe-vitamin D, ngoko i-25-(OH) VD ithathwa njengesona salathisi sokuvavanya izinga le-vitamin D.I-Diagnostic Kit isekelwe i-immunochromatography kwaye inokunika umphumo kwimizuzu eyi-15.