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CUH bone marrow aspirate sampling guidance (including MRD)
For controlled document please see Connect website on CUH Intranet.
At diagnosis of suspected acute leukaemia
Taken in order:
Bedside slides for morphology
2 mL in red EDTA for flow cytometry
3–5 mL in blue EDTA tube for molecular testing
2 mL in red EDTA for FISH
If suspected ALL, send one additional blue EDTA tube for identification of MRD markers (B and T)
2–5 mL in cytogenetics media for karyotyping
If definite acute leukaemia in peripheral blood, then trephine biopsy is not essential
Notes
The results of FISH and FLT3/NPM1 testing are important when choosing initial treatment. For expediency, please send separate samples for each test to avoid delays from sharing samples between laboratories.
In the event of a “dry tap”, a second trephine biopsy should be collected into a universal container (in 1 mL of sterile saline or RPMI) for disaggregation in order to perform the above tests. Additional PB samples should also be taken in EDTA and cytogenetics medium, and discussed with the HODS team.
AML follow up (suspected relapse)
If clinical suspicion of relapse after being in a documented remission:
Sample requirements same as for “diagnosis of suspected acute leukaemia”
AML follow up for MRD
If no clinical suspicion of relapse (i.e. blood counts stable and asymptomatic)
Bedside slides for morphology
3–5 mL in EDTA for molecular MRD assessment – labelled “first pull”
3 mL in EDTA for flow cytometry – FISH can be performed on this sample if relevant
If good/particulate aspirate obtained, do not need trephine biopsy post-chemotherapy. If insufficient aspirate obtained, review the pre-treatment blast phenotype. It is often very difficult to enumerate CD34-negative blasts on a trephine biopsy, so retry for a good aspirate sample. Please seek guidance from HODS team member or clinical consultant if uncertain of sample requirements.
Samples for RNA-based tests not performed in the East GLH, where molecular detection of genetic translocations is required (e.g. PML-RARA or RUNX1-RUNX1T1), or gene expression (e.g. NPM1 quantitation) should preferably arrive in the lab before 15:00 Monday to Thursday so these can be dispatched unprocessed to the appropriate external GLH laboratories without delay.
AML post-transplant
If no clinical suspicion of relapse (i.e. blood counts stable and asymptomatic):
Bedside slides for morphology
3–5 mL in EDTA for molecular MRD assessment – label “first pull”
2–3 mL in EDTA for flow cytometry
3 mL in EDTA for BM chimerism
Trephine biopsy should be included as part of the “Day +100” post-transplant assessment; however, it is not required with every BM biopsy in the post-transplant setting provided that a good/particulate aspirate sample has been obtained, blood counts are stable, and there are no clinical concerns of graft failure
ALL follow up for MRD
Post phase 1, and subsequent cycles
Post phase 1, and subsequent cycles (note: post phase 1 is a decision point for UKALL2011 protocol, and post course 2 is a decision point for UKALL14 protocol, but sample requirements are the same):
Bedside slides for morphology
3–5 mL in EDTA for molecular MRD assessment (IgH/TCR rearrangements for Ph– ALL, BCR-ABL1 for Ph+ ALL)
3 mL in EDTA for flow cytometry
Usually do not need trephine
ALL post-transplant (routine)
Bedside slides for morphology
3–5 mL in EDTA for molecular MRD assessment (IgH/TCR rearrangements for Ph– ALL, BCR-ABL1 for Ph+ ALL)
3 mL in EDTA for flow cytometry
3 mL in EDTA for BM chimerism
Trephine biopsy should be included as part of the “Day +100” post-transplant assessment; however, it is not required with every BM biopsy in the post-transplant setting provided that a good/particulate aspirate sample has been obtained, blood counts are stable, and there are no clinical concerns of graft failure
Pancytopenia of unknown cause
Sample requirements same as for “diagnosis of suspected acute leukaemia”
Suspected myeloma or lymphoma
Bedside slides for morphology
3 mL red EDTA for flow cytometry
3 mL red EDTA for FISH
Trephine (important as myeloma is a patchy disease)
Suspected non-CML MPN
Bedside slides for morphology
3 mL EDTA for flow cytometry and FISH if needed
3 mL EDTA for molecular testing
5–10 mL in cytogenetics media for karyotyping (usually not required)
Trephine (often the most diagnostic test so important to obtain an adequate sample)
Suspected CML
Sample requirements same as for “Suspected non-CML MPN” but no trephine needed if good/particulate aspirate obtained