NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Assessment of possible central nervous system or cardiac toxicity associated with use of bupivacaine or levobupivacaine
Gas Chromatography-Mass Spectrometry (GC-MS)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube: Red top
Specimen Volume: 1.5 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Mild OK; Gross reject
Mild OK; Gross reject
Mild OK; Gross reject
Arterial draw or serum gel tube
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Serum Red||Refrigerated (preferred)||14 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Bupivacaine (1-butyl-N-[2,6-dimethylphenyl] piperidine-2-carboxamide) is used as a local anesthetic for many surgical procedures, and is injected directly into surgical sites to reduce pain for up to 20 hours postsurgery. As an injectable local anesthetic, the drug is used to effect peripheral, sympathetic, caudal, epidural, or retrobulbar nerve membrane permeability to sodium ions, which results in inhibition of depolarization with resultant conduction blockade.(1)
The onset and duration of anesthesia is route- and dose-dependent, ranging from 1 to 17 minutes and lasting for 2 to 9 hours.(1) The drug is highly protein bound (approximately 95%), and has a volume of distribution (Vd) of 0.4 L/kg to 1.0 L/kg. Bupivacaine under goes significant metabolism; <1% of a dose is excreted unchanged.(2) The half-life elimination is age-dependent: approximately 8 hours in neonates and 1.5 to 5.5 hours in adults.(1)
Serum levels of bupivacaine correlate poorly with anesthesia effect because the drug's distribution out of the injection site is variable. However, serum levels may have value in indicating potential toxicity remote from the injection site. In general, central nervous system (CNS) and cardiovascular events are the primary toxicities and include tremor, tinnitus, dizziness, blurred vision, hypotension, and bradycardia. CNS symptoms of toxicity appear at lower serum levels than do cardiovascular symptoms.(3) Intralipid has been proposed as a treatment for the cardiotoxicity, but neither the optimum dose nor guidelines for intervention have been defined, so its use remains controversial and limited to those cases of cardiotoxicity when cardiopulmonary bypass is the only other option.
The drug is now available as the principally active optical isomer, levobupivacaine (this assay measures levobupivacaine and the racemic mixture [levobupivacaine and bupivacaine] equally). The occurrence of CNS toxicity with use of levobupivacaine is 1.5 to 2.5 times lower than with bupivacaine, from studies in healthy volunteers, with CNS toxicity onset coming at approximately 25% higher doses.(4) Since both drugs are often administered for local anesthesia at levels near the top of the tolerated range, it has proven difficult to objectively assess potency, and there is no clear conclusion as to which drug is more potent.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
No established reference values
In trials with healthy volunteers, the threshold for central nervous system (CNS) toxicity has been reported at 2.1 (+/- 1.2) mg/L following intravenous infusion,(3) and in another trial, 13 of 14 healthy volunteers reported signs of CNS toxicity at 2.25 mg/L of racemic bupivacaine.(5) Cardiovascular symptoms were reported in many fewer subjects, indicating slightly higher threshold for cardiovascular toxicity.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This assay is to be used only for serum drawn from a vein. Arterial levels are approximately twice venous levels and no clear relationship between arterial levels and toxicity has been established.(3)
This assay measures only total bupivacaine; levels of the free (unbound) portion may correlate more closely with symptoms.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Physician's Desk Reference (PDR). 61st edition. Montvale, NJ. Thomson PDR, 2007
2. Baselt RC: Disposition of Toxic Drugs and Chemicals in Man. 7th edition. Foster City, CA, Biomedical Publications, 2004, p 1254
3. Knudsen K, Beckman SM, Blomberg S, et al: Central nervous and cardiovascular effects of i.v. infusions of ropivacaine, bupivacaine and placebo in volunteers. Br J Anaesth 1997;78:507-514
4. Zink W, Graf BM: The toxicity of local anesthetics: the place of ropivacaine and levobupivacaine. Curr Opin Anaesthesiol 2008;21:645-650
5. Bardsley H, Gristwood R, Baker H, et al: A comparison of the cardiovascular effects of levobupivacaine and rac-bupivacaine following intravenous administration to healthy volunteers. Br J Clin Pharmacol 1998;46:245-429
Method Description Describes how the test is performed and provides a method-specific reference
Bupivacaine is extracted from serum using liquid-liquid extraction. The extracted specimen is dried down, reconstituted, and subsequently analyzed by gas chromatography/mass spectrometry (GC-MS) using an ion-selective detector. (Unpublished Mayo method)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday; 2nd shift
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Same day/1 day
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Serum: 2 weeks
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
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 Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|29900||Chain of Custody||In Process|