TNC stands for Total Nucleated Cells which are the white blood cells within a cord blood sample. Smart Cells count these cells as this is an important measurement of the success of the collection in terms of cell numbers. Within the TNC cell fraction, the Smart Cells team look at numbers of CD34 positive cells. This is a critical measurement as CD34 is a marker of stem cells. Both TNC and CD34 levels in a cord blood sample are taken into account by clinical teams when deciding if there are sufficient stem cells for treatment.