Bone Marrow Aspirate Collection Tubes for Persistent ITP in Children
For bone marrow aspirate in a child with persistent ITP, use sodium heparin tubes (20 IU/mL concentration), not EDTA or lithium heparin tubes. 1
Tube Selection and Collection Protocol
The most recent and authoritative guidance comes from the 2024 ACMG technical laboratory standards for cytogenomic studies, which provides explicit specifications for bone marrow collection 1:
Preferred Anticoagulant
- Sodium heparin at 20 IU/mL is the standard anticoagulant for bone marrow aspirate
- This concentration should be calculated based on either bone marrow volume alone OR total volume of bone marrow plus transport medium combined
- Sodium heparin prevents coagulation without interfering with cell culture or diminishing preparation quality
Tubes to Avoid
- Do NOT use lithium heparin tubes - these are explicitly not recommended 1
- EDTA tubes are not the preferred choice for initial collection, though research shows EDTA-preserved samples can produce adequate slides if prepared at the end of the procedure 2
Important Context: When Bone Marrow is Actually Needed
Critical caveat: The 2011 ASH guidelines for ITP strongly recommend that bone marrow examination is NOT necessary in children with persistent ITP (Grade 1B recommendation) 3. This applies to:
- Children with typical ITP features at diagnosis
- Children who fail IVIg therapy
- Before initiating corticosteroids or splenectomy (Grade 2C)
When Bone Marrow IS Indicated
Bone marrow examination should only be performed if atypical features develop 3:
- Fever or bone/joint pain
- Family history of thrombocytopenia
- Skeletal or soft-tissue abnormalities
- Non-petechial rash
- Lymphadenopathy or hepatosplenomegaly
- Abnormal hemoglobin, white blood cell count, or white cell morphology
Collection Specifications
If bone marrow aspirate is clinically indicated:
Volume: 1-3 mL (children require less than adults) 1
Timing: First or second draw is preferred as it contains more neoplastic/diagnostic cells before hemodilution occurs 1
Transport:
- Maintain at ambient temperature
- Deliver to laboratory within 24 hours ideally
- Avoid extreme temperatures 1
Processing: Laboratory should process as soon as possible after receipt to preserve specimen integrity 1
The sodium heparin tube specification is consistent across hematologic specimen collection and ensures optimal cell viability for both cytogenetic analysis and morphologic evaluation.