Which blood film finding indicates EDTA-induced pseudothrombocytopenia?

Pseudothrombocytopenia induced by EDTA (ethylenediaminetetraacetic acid) is characterized by an artifact in the blood film due to the aggregation of platelets. When EDTA is used as an anticoagulant, it can cause some platelet populations to clump together, which may result in the appearance that there are fewer platelets present when counted.

In the context of the question, the finding of platelets adhering to white blood cells (WBCs) is a key indicator of this condition. Such platelet aggregation often leads to a misleadingly low platelet count on automated blood cell counters, as the aggregates may be counted as larger cells. Consequently, while the actual number of platelets may be normal or high, the appearance in the blood smear will show them clustered around WBCs, reflecting this pseudothrombocytopenic state.

Observations such as platelets being pushed to the feathered edge, not seeing platelets at all, or a bluish discoloration of the slide are not specific indicators of EDTA-induced pseudothrombocytopenia. These findings may occur due to other factors and do not reflect the specific aggregation process characteristic of this situation. Thus, the adherence of platelets to