Opening laboratory problem

An EDTA outpatient specimen collected at 09:05 is analyzed at 10:02. The CBC is flagged for leukocytosis, immature granulocytes, and manual differential review. White blood cells are 86.4 × 10^9/L against a local interval of 4.0 to 11.0 × 10^9/L, hemoglobin is 11.8 g/dL, and platelets are 612 × 10^9/L. The question is which smear pattern should raise concern for BCR::ABL1-positive chronic myeloid leukemia, or CML, and what the laboratory should do next.

The manual differential at 10:35 has segmented neutrophils 42%, bands 8%, metamyelocytes 12%, myelocytes 21%, promyelocytes 5%, blasts 1%, eosinophils 5%, basophils 4%, lymphocytes 1%, and monocytes 1%. Absolute basophils are 3.46 × 10^9/L and absolute eosinophils are 4.32 × 10^9/L. The smear comment is marked left-shifted granulopoiesis with a prominent myelocyte population, absolute basophilia, and eosinophilia. This supports a CML-pattern smear but does not establish CML.

Start with the observed distribution rather than a disease label. The useful clue is cells across the granulocytic maturation continuum with a prominent myelocyte population, sometimes called a myelocyte bulge. Thrombocytosis can support the pattern but is not required because platelets may be normal or increased in chronic-phase CML. Release the verified CBC and smear interpretation through the local review pathway, then document the pattern that warrants BCR::ABL1 workup.