Differential Diagnosis of Blasts in Blood Smears: Common Errors

Analysis of typical errors in blood smear microscopy: why blast cells are mistaken for reactive lymphocytes and how to suspect acute leukemia in time.

Editorial team 1 min April 1, 2025

Blood smear, accumulation of blast cells with visible nucleoli

The correct answer to the closed club of laboratory hematologists’ challenge. D) 3 errors

🧾 Explanation: The resident made three serious errors:

There is no leukopenia — leukopenia cannot be diagnosed without a complete blood count, especially from a single field of view of a smear.
There are no reactive lymphocytes — there are no lymphocytes in the smear, let alone reactive ones. All cells are blasts, which is characteristic of hemoblastoses, not viral infections.
This is not “viral blood” — neither the cytological picture nor the cellular composition of the smear shows signs of viral infection. The conclusion about a “patient with a virus” is fundamentally erroneous.

📌 In such a situation, the correct conclusion is a suspicion of acute leukemia and urgent further investigation.

🏆 Congratulations to the winners! They receive a private invitation to the club of selected specialists.