Pancytopenia is a reduction in all three major blood cell lines in peripheral blood:

It is a laboratory finding, not a diagnosis by itself. Symptoms may include fatigue or dyspnea from anemia, recurrent infections from leukopenia, and bruising or bleeding from thrombocytopenia. Merck Manual

There is no single universal cutoff. Pancytopenia means all 3 cell lines are below the laboratory’s normal range.

A commonly used adult definition is:

All three should be reduced to label it pancytopenia. Some sources instead use lower limits of normal, such as Hb <13 g/dL in men or <12 g/dL in women, WBC <4,000/µL, and platelets <150,000/µL. Therefore, use your local laboratory reference intervals clinically. A 2024 clinical review uses the first set of thresholds. Review article