ABPath Hematopathology common mistakes
ABPath Hematopathology · Understand the traps and how to avoid them.
Calling a flow cytometry population positive from a single aberrant marker without confirming intensity, co-expression, and internal negative controls.
Candidates often rely on memorized single-marker positivity and forget that weak cross-reactivity, nonspecific binding, and small normal subsets can mimic disease.
What to do instead
Use multidimensional gating, compare marker intensity with normal internal controls, and require co-expression or morphology/immunohistochemistry support before calling a abnormal population.
Assigning bone marrow cellularity as normal or abnormal using adult norms without adjusting for patient age, prior therapy, or marrow site.
Hematopoiesis changes with age and treatment, and candidates often apply a single 50% threshold reflexively.
What to do instead
State the age-adjusted expectation, note prior chemotherapy or growth factor exposure, and correlate cellularity with peripheral counts and lineage maturation.
Diagnosing iron deficiency from a low ferritin alone in a patient with inflammation, infection, or liver disease.
Ferritin is an acute-phase reactant, so candidates may ignore inflammatory masking of iron deficiency or overinterpret a normal ferritin.
What to do instead
Interpret ferritin with CRP, transferrin saturation, and soluble transferrin receptor; use marrow iron or therapeutic trial when the picture remains ambiguous.
Labeling left-shifted neutrophils as dysplasia or a myeloproliferative neoplasm without first excluding toxic granulation, Döhle bodies, and reactive neutrophilia.
Reactive myeloid changes overlap morphologically with dysplasia, and candidates often over-weight a few atypical cells.
What to do instead
Quantify the abnormality, assess toxic changes and clinical context, and require persistent unexplained dysplasia or supporting flow/cytogenetic/molecular data.
Overcalling small B-cell clonality on flow cytometry from a mildly skewed kappa/lambda ratio without considering population size and antigen maturity.
Small normal B-cell subsets can show apparent light-chain skew, and candidates may treat any ratio outside a reference range as lymphoma.
What to do instead
Require an absolute clonal B-cell count, abnormal antigen expression, and correlation with morphology or histology before diagnosing a B-cell neoplasm.
Staging marrow involvement from a single unilateral biopsy in a disease known to be patchy, such as lymphoma or metastatic carcinoma.
Sampling error is common, and candidates may accept one core as definitive without integrating imaging or ancillary studies.
What to do instead
Recommend bilateral biopsies when clinically appropriate, use flow cytometry or immunohistochemistry, and state the sampling limitation in the report.
Diagnosing immune thrombocytopenia before reviewing the smear for platelet clumping or excluding EDTA-dependent pseudothrombocytopenia.
Automated platelet counts can be falsely low from clumping, and candidates may proceed to treatment without smear confirmation.
What to do instead
Review the peripheral smear, repeat the count in citrate or heparin, perform a manual phase-contrast count, and exclude pseudothrombocytopenia before therapy.
Interpreting a mixing study as correction without distinguishing immediate from incubated results and without confirming the suspected factor deficiency.
Immediate correction can occur with factor deficiency, but some inhibitors are time-dependent; candidates often stop at the immediate result.
What to do instead
Perform and report both immediate and incubated mixing studies, then confirm with specific factor assays and inhibitor testing when indicated.
Recommending red-cell transfusion for a stable patient solely because hemoglobin is below a numeric threshold, without assessing symptoms, bleeding, or volume status.
Threshold-driven practice is easy to memorize, but transfusion decisions require clinical context and restrictive-strategy evidence.
What to do instead
Integrate symptoms, rate of fall, comorbidity, and volume status; use restrictive thresholds for stable patients and document the indication.
Issuing a hematopathology diagnosis from one data stream, such as morphology or flow alone, without reconciling cytogenetics, molecular results, and clinical history.
Subspecialty data are often reviewed in silos, and candidates may finalize before all ancillary results are available.
What to do instead
Create an integrated diagnostic summary that reconciles morphology, immunophenotype, cytogenetics, molecular findings, and history; explicitly note unresolved discordance and recommended follow-up.