Ikhithi yokufumanisa ivithamin D (igolide ye-colloidal) ilungele ukufunyanwa kwe-semi-quantitative ye-vitamin D kwigazi le-venous lomntu, i-serum, i-plasma okanye igazi le-peripheral, kwaye ingasetyenziselwa ukuhlola izigulane ukunqongophala kwe-vitamin D.