Differential display (DD) is widely employed for identifying uniquely expressed genes within two different cell populations. While potentially powerful, DD is problematic because apparent positive clones require time-consuming verification which may be made even more difficult if only small amounts of starting material are available. We have devised a screening approach to address these issues in primary human hematopoietic cells. Candidate clones are identified in a slot-blot format and verified by'Virtual Northern'blot analyses using globally amplified cDNA as the verification probe. This method is fast, and since it requires only 0.2 μg of total RNA, it is particularly useful when only limited amounts of study tissue are available.