A method for detecting and manipulating tumor cells found in organic fluids comprising the steps of: a) providing a liquid specimen of the organic fluid containing an enriched population of tumor cells and a population of non-tumor cells; b) fluorescently staining at least one of the two cell populations wherein a different fluorescence dye is used for each population when both populations are stained; c) providing a donor substrate comprising a transparent support and a semi-transparent polymeric adhesive tape adhered to the transparent support; d) dispensing and spreading the liquid specimen onto the semi-transparent polymeric adhesive tape; e) providing a receiving substrate; f) placing the receiving substrate facing the surface of the donor substrate where the liquid specimen is spread maintaining a separation distance between them; g) visualizing the same portion of the liquid specimen by means of optical and fluorescence microscopy; h) comparing the optically and fluorescently obtained images to identify the location of tumor cells or non-tumor cells; i) providing a laser beam focused on the interface between the transparent support and the semi-transparent polymeric adhesive tape of the donor substrate; j) directing the laser beam to the identified location of at least one tumor cell or at least one non-tumor cell; so that the laser beam energy is absorbed by the semi-transparent polymeric adhesive tape at the identified location; giving place to the formation of a blister on the polymeric adhesive tape that generates a mechanical perturbation in the liquid specimen leading to the movement of at least one cell or cluster of cells. a) providing a liquid specimen of the organic fluid containing an enriched population of tumor cells and a population of non-tumor cells; b) fluorescently staining at least one of the two cell populations wherein a different fluorescence dye is used for each population when both populations are stained; c) providing a donor substrate comprising a transparent support and a semi-transparent polymeric adhesive tape adhered to the transparent support; d) dispensing and spreading the liquid specimen onto the semi-transparent polymeric adhesive tape; e) providing a receiving substrate; f) placing the receiving substrate facing the surface of the donor substrate where the liquid specimen is spread maintaining a separation distance between them; g) visualizing the same portion of the liquid specimen by means of optical and fluorescence microscopy; h) comparing the optically and fluorescently obtained images to identify the location of tumor cells or non-tumor cells; i) providing a laser beam focused on the interface between the transparent support and the semi-transparent polymeric adhesive tape of the donor substrate; j) directing the laser beam to the identified location of at least one tumor cell or at least one non-tumor cell; so that the laser beam energy is absorbed by the semi-transparent polymeric adhesive tape at the identified location; giving place to the formation of a blister on the polymeric adhesive tape that generates a mechanical perturbation in the liquid specimen leading to the movement of at least one cell or cluster of cells.