A CBC Pattern That Needs More Evidence

An EDTA whole-blood specimen collected at 08:10 and received at 08:28 has hemoglobin 8.7 g/dL, mean corpuscular volume 106 fL, white blood cells 2.6 × 10^9/L, absolute neutrophil count 0.9 × 10^9/L, and platelets 76 × 10^9/L. The adult local intervals are 12.0-16.0 g/dL, 80-100 fL, 4.0-11.0 × 10^9/L, 1.8-7.7 × 10^9/L, and 150-400 × 10^9/L. The smear-review flag leads to manual microscopy, which shows macro-ovalocytes, anisopoikilocytosis, occasional hypogranular hypolobated neutrophils, and platelet size variation. These findings raise concern but do not establish myelodysplastic neoplasm, or MDS, from peripheral morphology alone.

Begin by preserving the distinction between what the methods measure and what the pattern may mean. The analyzer measures counts and indices, while the smear is a manual morphologic assessment. Persistent cytopenia, macrocytosis, and dysplastic-appearing cells can fit MDS, but they can also occur with reversible or reactive conditions. Compare the blood count trend, differential, smear quality, and clinical context before proposing marrow evaluation.

WHO-HAEM5 uses harmonized cytopenia thresholds of hemoglobin below 13 g/dL in males or 12 g/dL in females, absolute neutrophil count below 1.8 × 10^9/L, and platelets below 150 × 10^9/L for clonal cytopenia of undetermined significance (CCUS), MDS, and MDS/MPN contexts. CCUS is persistent unexplained cytopenia with clonal evidence that does not meet criteria for a defined myeloid neoplasm. Those are classification thresholds, not this laboratory's reference intervals. This case is clearly cytopenic by both its local intervals and the WHO thresholds, yet classification still requires integrated evidence. Release the measured CBC and document the smear pattern, then escalate persistent unexplained cytopenia through the local review pathway.