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25445 Carbamazepine 10,11 Epoxide (CARBG)

Carbamazepine 10,11 Epoxide (CARBG)
Test Code: C1011SO
Synonyms/Keywords
Carbamazepine (Carbatrol, Tegretol)
Carbamazepine Epoxide
Carbamazepine Metabolite
Carbatrol (Carbamazepine)
Epoxide 10, 11
Tegretol (Carbamazepine)
Useful For
​Monitoring patients exhibiting symptoms of carbamazepine toxicity whose total serum carbamazepine concentration is within the therapeutic range, but who may be producing significant levels of the active metabolite epoxide, which can accumulate to concentrations equivalent to carbamazepine
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)​​
​No ​Serum ​Red Top Tube (RTT) ​ ​2.0 mL ​1.0 mL ​
Collection Processing Instructions
​Draw sample 12 hours (trough value) after last dose
Specimen Stability Information
Specimen Type Temperature Time​​
Serum​ ​ ​ ​Refrigerated (preferred) ​7 days
​Ambient 48 hours
​Frozen ​28 days
Rejection Criteria
​Gross Hemolysis
Gross Lipemia​
​Gross Icterus
​Serum Separator Tube
Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available Methodology/Instrumen​​tation
​Mayo Clinic Laboratories

CARTA:  Monday through Sunday

1011E:  Tuesday

 ​1 to 7 days

CARTA:  Homogeneous Microparticle Agglutination Immunoassay

1011E:  High-Performance Liquid Chromatography (HPLC)

Reference Lab
Mayo Clinic Laboratories
Reference Range Information
Performing Location Reference ​​Range
Mayo Clinic Laboratories​ ​ ​Carbamazepine, Total
   Therapeutic: 4.0-12.0 mcg/mL
   Critical value: > or = 15.0 mcg/mL
​Carbamazepine-10, 11 Epoxide
   Therapeutic concentration: 0.4-4.0 mcg/mL
   Toxic concentration: > or = 8.0 mcg/mL
Interpretation

The clinically acceptable serum concentration of carbamazepine-10,11-epoxide (CBZ10-11) is not well established, but 4.0 mcg/mL has often been used as an upper limit for its therapeutic range. 

The ratio of CBZ10-11 to carbamazepine is usually < or =0.2 mcg/mL in symptomatic adults and < or =0.3 mcg/mL in children. 

Clinical correlation is aided by comparing values obtained when the patient is symptomatic with those obtained when the patient has improved.

Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Commen​​ts
80156 ​ ​1 ​Assay Carbamazepine total ​
80161 ​ ​1 ​Quantitative assay drug ​
Synonyms/Keywords
Carbamazepine (Carbatrol, Tegretol)
Carbamazepine Epoxide
Carbamazepine Metabolite
Carbatrol (Carbamazepine)
Epoxide 10, 11
Tegretol (Carbamazepine)
Ordering Applications
Ordering Application Description
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)​​
​No ​Serum ​Red Top Tube (RTT) ​ ​2.0 mL ​1.0 mL ​
Collection Processing
​Draw sample 12 hours (trough value) after last dose
Specimen Stability Information
Specimen Type Temperature Time​​
Serum​ ​ ​ ​Refrigerated (preferred) ​7 days
​Ambient 48 hours
​Frozen ​28 days
Rejection Criteria
​Gross Hemolysis
Gross Lipemia​
​Gross Icterus
​Serum Separator Tube
Useful For
​Monitoring patients exhibiting symptoms of carbamazepine toxicity whose total serum carbamazepine concentration is within the therapeutic range, but who may be producing significant levels of the active metabolite epoxide, which can accumulate to concentrations equivalent to carbamazepine
Reference Range Information
Performing Location Reference ​​Range
Mayo Clinic Laboratories​ ​ ​Carbamazepine, Total
   Therapeutic: 4.0-12.0 mcg/mL
   Critical value: > or = 15.0 mcg/mL
​Carbamazepine-10, 11 Epoxide
   Therapeutic concentration: 0.4-4.0 mcg/mL
   Toxic concentration: > or = 8.0 mcg/mL
Interpretation

The clinically acceptable serum concentration of carbamazepine-10,11-epoxide (CBZ10-11) is not well established, but 4.0 mcg/mL has often been used as an upper limit for its therapeutic range. 

The ratio of CBZ10-11 to carbamazepine is usually < or =0.2 mcg/mL in symptomatic adults and < or =0.3 mcg/mL in children. 

Clinical correlation is aided by comparing values obtained when the patient is symptomatic with those obtained when the patient has improved.

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available Methodology/Instrumen​​tation
​Mayo Clinic Laboratories

CARTA:  Monday through Sunday

1011E:  Tuesday

 ​1 to 7 days

CARTA:  Homogeneous Microparticle Agglutination Immunoassay

1011E:  High-Performance Liquid Chromatography (HPLC)

Reference Lab
Mayo Clinic Laboratories
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Commen​​ts
80156 ​ ​1 ​Assay Carbamazepine total ​
80161 ​ ​1 ​Quantitative assay drug ​
For most current information refer to the Marshfield Laboratory online reference manual.