Synopsis
Select bone-marrow aspiration, trephine biopsy and ancillary studies for a defined clinical question, prepare the patient safely and translate morphology, flow and genetics into a coherent diagnosis.
- Define the question before the procedure: unexplained cytopenia, suspected acute leukaemia, myelodysplasia, marrow infiltration, plasma-cell disorder, lymphoma staging, fibrosis, storage disease or fever of unknown cause each needs different samples.
- Aspiration provides individual-cell morphology, differential counts, flow cytometry, cytogenetics, molecular tests and microbiology; the trephine preserves architecture, cellularity, fibrosis, focal infiltrates and spatial relationships.
- Most adult samples come from the posterior iliac crest. Sternal aspiration is an expert-only alternative in selected circumstances and cannot provide a trephine; the sternum is not used for routine biopsy.
- Check identity, indication, consent, allergies, pregnancy status where relevant, infection, platelet and coagulation context, antithrombotic medicines, positioning and the exact laboratory containers before starting.
- A dry tap is information, not merely failure. Fibrosis, packed leukaemia, metastatic infiltration and technical factors can prevent aspiration, making trephine touch imprints and core quality especially important.
- Collect aspirate promptly because dilution increases with repeated pulls. Direct the first material to morphology and the highest-priority ancillary test agreed with the laboratory.
- A normal aspirate does not exclude patchy disease or architectural abnormality. Conversely, a hypocellular aspirate may reflect dilution and must be reconciled with trephine cellularity.
- Results require integration at a multidisciplinary level: morphology, immunophenotype, karyotype, fluorescence studies and molecular variants can conflict or describe different parts of one clonal process.
Key red flags
Blasts, abnormal promyelocytes, rapidly worsening cytopenias, infection, bleeding or leukostasis symptoms require urgent blood and marrow classification within an emergency haematology pathway.
Persistent bleeding, syncope, severe escalating buttock or back pain, neurological change, fever or wound discharge after sampling requires immediate examination and cause-directed imaging or treatment.
Investigation priorities
Confirm the indication and plan bleeding-risk mitigation before an invasive sample.
Management branches
Persistent blood, clinical or imaging abnormalities raise a marrow diagnosis but immediate instability has been addressed.
- Review peripheral film, reticulocytes, haematinics, haemolysis, renal, liver, infection, imaging and medicine causes first, documenting the unresolved question that marrow should answer.
- The preferred plan is combined aspirate and trephine when cellularity, architecture or infiltration matters; aspiration alone is an alternative only when the specific question is cytological and the core would not add value.
- Escalate urgent suspected acute leukaemia, aplasia or aggressive infiltration to the specialist team so sampling, supportive care and treatment timing are coordinated rather than scheduled routinely.