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Paediatric Laboratory Medicine


Clinical Significance

Busulfan is a bifunctional alkylating agent which has been in clinical use since 1959. Carbonium ions are rapidly formed after absorption of Busulfan, leading to the alkylation of DNA. This results in breakage of the DNA molecule as well as the cross-linking of the strands. As a result, DNA replication and subsequent RNA transcription is interfered with. The antitumour activity of Busulfan is cell cycle phase-nonspecific.

Recipient conditioning for Bone Marrow Transplantation is an important determinant in the overall clinical outcome in the treatment of many diseases, both malignant (Acute and Chronic Leukemia's) and non-malignant (Thalassemia Major). High dose Busulfan (1,4-butanediyl dimethanesulfonate), followed by Cyclophosphamide is one of the regimens used in preparing the patient for the bone marrow procedure.

Busulfan is used as an alternative to total body irradiation in preparative regimens for bone marrow transplantation. However, as with radiation, Busulfan conditioning is still troubled by severe toxicities that limit its applications to suboptimal drug doses. Some of the more common side effects include:

  • Myelosuppression
  • Pancytopenia
  • Central Nervous System disturbances (seizures)
  • Pulmonary (shortness of breath, cough)
  • Gastrointestinal (nausea, vomiting, diarrhea)
  • Hepatic (Veno-occlusive disease)
  • Soreness of the mouth, difficulty swallowing
  • Hair loss 

Individualized dosing is based on monitoring the first dose pharmokinetics.

Test Name


Alternate Name/ Synonym


Test Code


Drug Class



Therapeutic Drug Monitoring - TDM



External Proficiency Testing

Inter-Laboratory Comparison

Turn Around Time

Day of receipt



Specimen Type

Plasma (Heparin)

Minimum Specimen Requirements

250 uL

Optimal Collection Time

Protocol Dependent


-20°C (transport on dry ice)

Special Requirements

Must notify lab (416-813-5906) if samples are being collected and shipped.

Approval is not required

CPT Codes


Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Phone: 416-813-7200
Phone: 1-855-381-3212

Therapeutic Range

Protocol Dependent