use option in numpy.genfromtxt for reading the first column only

            ref_tracefile_dec = f"{reference_path}/param_file/dec/{tracefile_dec}"

            # check for same RTP sequence number in last line of tracefile

            with open(dut_tracefile_dec,"r") as fp:

                lines = [l for l in fp.readlines() if not l.startswith("-1")]

                dut_rtp_num_last = lines[-1][0]

            with open(ref_tracefile_dec,"r") as fp:

                lines = [l for l in fp.readlines() if not l.startswith("-1")]

                ref_rtp_num_last = lines[-1][0]

            dut_rtp_num_last = np.genfromtxt(dut_tracefile_dec, delimiter=";", usecols=[0])[-1]

            ref_rtp_num_last = np.genfromtxt(ref_tracefile_dec, delimiter=";", usecols=[0])[-1]

            tracefile_last_rtp_numbers_differ = dut_rtp_num_last != ref_rtp_num_last

        # same sequence number -> likely no crash, assume length difference is due to difference in TSM