1. A method comprising in order: (a) treating a biological sample having chromosomal material therein with one or more antibodies having an affinity for at least one non-chromosomal portion of such biological sample, the antibody(ies) having an introduced non-detectable reactive conjugate thereon; (b) treating said biological sample with a fluorescently-tagged chromosome probe having a high degree of sequence similarity to one or more portions of said chromosomic material; and (c) treating said biological sample with a detectable tag reactive with said non-detectable reactive conjugate on said antibody(ies) but not with said chromosomal material or non-chromosomal portions of said biological sample.