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Test ID BUAUC Busulfan, Intravenous Dose, Area Under the Curve (AUC), Plasma

Useful For

Guiding dosage adjustments to achieve complete bone marrow ablation while minimizing dose-dependent toxicity

Profile Information

Test ID Reporting Name Available Separately Always Performed
DOSE Busulfan, IV Dose, AUC, P No Yes
BU2H Busulfan, Immediate Post Infusion No Yes
BU3H Busulfan, 1hr Post Infusion No Yes
BU4H Busulfan, 2hr Post Infusion No Yes
BU6H Busulfan, 4hr Post Infusion No Yes

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Reporting Name

Busulfan, IV Dose, AUC, P

Specimen Type

Plasma Na Heparin

Four plasma specimens with different draw times (keep all specimens under 1 order) and a completed Busulfan Information: Mail-In Specimen Instructions (T559) are required.

 

Collection Container/Tube: Green top (sodium heparin)

Submission Container/Tube: Plastic vials

Specimen Volume: 1 mL

Collection Instructions: 

1. The first specimen should be drawn immediately after termination of intravenous infusion of 0.8 mg/kg busulfan.

2. Additional specimens should also be drawn at 1 hour, 2 hours, and 4 hours after termination of infusion.

3. Label each specimen appropriately (exact time of draw).

4. Busulfan degrades quickly at room temperature. Each specimen should be kept in wet ice slurry or refrigerated at 4° C. Specimen should be centrifuged as soon as possible after collection. Separate the plasma from each specimen and transfer it to individual 5-mL plastic tubes. Immediately freeze these plasma specimens at -20° C.

Forms: Busulfan Information: Mail-In Specimen Instructions (T559) in Special Instructions

Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time
Plasma Na Heparin Frozen (preferred) 28 days
  Refrigerated  72 hours

Clinical Information

Busulfan is an alkylating agent used to ablate bone marrow cells prior to hematopoietic stem cell transplantation for chronic myelogenous leukemia.(1) Busulfan is typically administered intravenously (IV) at the recommended dosage of 0.8 mg/kg of actual or ideal body weight (whichever is lower) and given once every 6 hours over 4 days for a total of 16 doses. Dose-limiting toxicity of busulfan includes veno-occlusive liver disease, seizures, and coma. To avoid toxicity while ensuring busulfan dose adequacy to completely ablate the bone marrow, IV dosing should be guided by pharmacokinetic (PK) evaluation of area under the curve (AUC) and clearance after the first dose.(2) The PK evaluation should be carried out at the end of the first dose, with results of PK testing available to facilitate dose adjustment before beginning the fifth dose.

Reference Values

AREA UNDER THE CURVE

900-1,500 (mcmol/L)(min)

 

CLEARANCE

2.1-3.5 (mL/minute)/kg

Cautions

This assay requires 4 plasma specimens. Each specimen must be drawn at the intervals described above and labeled with the exact draw time. The specimen accession times should reflect these times. The time the drug administration is started and terminated, the patient's dose (mg every 6 hours), body weight (kg), and age (years) must be submitted with the specimens. Without infusion start time, exact time of specimen draw, dose, and body weight, the area under the curve and clearance cannot be calculated. Age is required for assessment of the correct dose per body weight. 

Day(s) Performed

Monday through Saturday; 2 p.m.

Report Available

Same day/1 day

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

80299 x 4

NY State Approved

Yes