Test Code BUAUC Busulfan, Intravenous Dose, Area Under the Curve, Plasma
Reporting Name
Busulfan, IV Dose, AUC, PPerforming Laboratory
Mayo Clinic Laboratories in RochesterUseful For
Guiding dosage adjustments to achieve complete bone marrow ablation while minimizing dose-dependent toxicity
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Necessary Information
The time the drug administration is started and completed, 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 collection, 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.
A completed Busulfan Information: Mail-In Specimen Instructions (T559) is required.
Specimen Required
Four plasma specimens with different collection times (keep all specimens under 1 order) are required.
Collection Container/Tube: Green top (sodium heparin) (Plasma gel/PST are not acceptable)
Submission Container/Tube: Plastic vials
Specimen Volume: 1 mL
Collection Instructions:
1. The first specimen should be collected immediately after completion of the first intravenous infusion of 0.8 mg/kg busulfan.
2. Additional specimens should also be collected at 1 hour, 2 hours, and 4 hours after completion of infusion.
3. Label each specimen with exact time of collection.
4. Busulfan degrades quickly at ambient temperature. Specimens must be kept in wet ice slurry or refrigerated at 4° C. Specimens must be centrifuged within 2 hours after collection. Separate the plasma and transfer to individual 5-mL plastic vials, labeled with exact time of collection. Immediately freeze at -20° C.
Additional Information:
This test should only be ordered when the following criteria are met:
-Busulfan dosing protocol must be intravenous administration of 0.8 mg/kg doses every 6 hours over 4 days, for a total of 16 doses
Specimens must be collected as described below:
-1 specimen collected immediately after completion of the first 2-hour IV infusion of busulfan
-1 specimen collected 1 hour after the infusion is completed
-1 specimen collected 2 hours after the infusion is completed
-1 specimen collected 4 hours after the infusion is completed and prior to the next infusion of busulfan
Specimen Type
Plasma Na HeparinSpecimen Minimum Volume
0.25 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Plasma Na Heparin | Frozen (preferred) | 28 days | |
Refrigerated | 72 hours |
Reject Due To
Gross hemolysis | OK |
Gross lipemia | OK |
Gross icterus | OK |
Reference Values
AREA UNDER THE CURVE
900-1500 (mcmol/L)(min)
CLEARANCE
2.1-3.5 (mL/minute)/kg
Interpretation
Results of the timed collections will be used to calculate a 6-hour area under the curve (AUC). If a different dosing or specimen collection protocol is used, or if different calculations are required, contact the Laboratory Director.
The optimal result for AUC (6 hour) derived from this pharmacokinetic evaluation of IV busulfan is 1100 (mcmol/L)(min).
Area under the curve results greater than 1500 (mcmol/L)(min) are associated with hepatic veno-occlusive disease. A dose reduction should be considered before the next busulfan infusion.
Area under the curve results below 900 (mcmol/L)(min) are consistent with incomplete bone marrow ablation. A dose increase should be considered before the next busulfan infusion.
Clearance of busulfan in patients with normal kidney function is usually in the range of 2.1 to 3.5 (mL/min)/kg.
Elevated AUC is typically associated with clearance below 2.5 (mL/min)/kg, most frequently due to diminished activity of glutathione S-transferase A1-1 activity.(3)
Day(s) Performed
Monday through Saturday
Report Available
Same day/1 to 3 daysTest Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80299 x 4
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
BUAUC | Busulfan, IV Dose, AUC, P | 93478-6 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
DRDT2 | Draw Date | 33882-2 |
DRDT3 | Draw Date | 33882-2 |
DRDT4 | Draw Date | 33882-2 |
DRDT6 | Draw Date | 33882-2 |
DSE | Initial Dose | 93477-8 |
DAT16 | Infusion Start Date | 88063-3 |
DRTM6 | Draw Time | 49049-0 |
DRTM4 | Draw Time | 49049-0 |
DRTM3 | Draw Time | 49049-0 |
DRTM2 | Draw Time | 49049-0 |
24221 | Busulfan result | 93436-4 |
24222 | Busulfan result | 93435-6 |
24223 | Busulfan result | 93434-9 |
24224 | Busulfan result | 93433-1 |
TM82 | Infusion Start Time | 88060-9 |
DAT17 | Infusion Stop Date | 88062-5 |
TM65 | Infusion Stop Time | 88061-7 |
W8 | Weight | 29463-7 |
24220 | Age | 30525-0 |
24225 | Area Under the Curve, (0-6 Hour) | 93476-0 |
24226 | Clearance | 93475-2 |
24227 | Recommended Dose | 93477-8 |
Forms
1. Busulfan Information: Mail-In Specimen Instructions (T559) is required
2. If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.
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 |