A diagnosis can be made on a small bone marrow specimen if diagnostic material is obtained. However, a certain amount of marrow must be collected to detect patchy disease, to perform all of the requested testing and to get an accurate picture of the hematopoietic cells.
Criteria for an adequate bone marrow collection in an adult:
(1) total core length >= 2 cm after processing (others use >= 1.5 cm; >= 3.0 cm may be needed to detect a focal lesion)
(2) core with >= 5 intertrabecular spaces containing hematopoietic cells
(3) aspirates containing intertrabecular cells (not only blood)
(4) sufficient for all of the requested testing (flow cytometry, cytogenetics, etc)
where:
• Shrinkage during can be up to 25%.
A second biopsy may result in a change in management by < 5% if the first specimen is adequate.
The greater the diameter of the core (lower gauge number) the greater the volume for a given length.
Problems:
(1) amount of cortical bone
(2) marrow fibrosis
(3) sterility in specimens submitted for culture
The pathology report should contain an assessment of the overall adequacy of the specimen(s) collected.
