Vitamin D yog ib qho vitamin thiab kuj yog ib qho tshuaj hormones steroid, feem ntau suav nrog VD2 thiab VD3, uas nws cov qauv zoo sib xws heev. Vitamin D3 thiab D2 raug hloov mus ua 25 hydroxyl vitamin D (suav nrog 25-dihydroxyl vitamin D3 thiab D2). 25-(OH) VD hauv tib neeg lub cev, kev tsim kho ruaj khov, muaj kev sib xyaw siab. 25-(OH) VD qhia txog tag nrho cov vitamin D, thiab lub peev xwm hloov pauv ntawm vitamin D, yog li 25-(OH) VD raug suav hais tias yog qhov qhia zoo tshaj plaws rau kev ntsuam xyuas qib ntawm vitamin D. Lub Khoom Siv Kuaj Mob yog raws li immunochromatography thiab tuaj yeem muab cov txiaj ntsig hauv 15 feeb.