The invention relates to methods for detecting allogeneic therapeutic cells (such as human umbilical cord tissue-derived cells (hUTC)) in blood. The methods includes the steps of identifying one or more one or more markers positive for allogeneic therapeutic cells (e.g. hUTC) and one or more markers positive for human peripheral blood mononuclear cells (PBMC); providing a blood sample from a patient that has been treated with allogeneic therapeutic cells (e.g. hUTC), analyzing the sample using an assay method to detect one or more markers positive for PBMC and one or more markers positive for allogeneic therapeutic cells (e.g. hUTC); and distinguishing between the PBMC and one or more markers positive for allogeneic therapeutic cells (e.g. hUTC). In one embodiment, the cells are hUTC and the markers positive of hUTC include CD10 and/or CD13 and the one or more markers positive for PBMC includes CD45.