carbamazepine in serum/plasma
Indications
monitoring therapy with carbamazepine
- drug overdose
- monitoring medical compliance
- therapeutic drug monitoring
- prophylactic management of seizures, epilepsy
- partial seizures
- mixed partial seizure disorder
- bipolar disorder (Equetro), mania
- attention-deficit hyperactivity disorder (ADHD)
- trigeminal neuralgia
- diabetic neuropathy
- neurogenic pain syndromes
- alcohol abuse
- cocaine abuse
- prophylactic management of seizures, epilepsy
Reference interval
Principle
The unique reagents in this methodology are the matched lots of anticarbamazepine antibody & the carbamazepine - glucose-6- phosphate dehydrogenase conjugate. The reaction sequence, in two steps, is as shown:
CRBAM <-------- Ab CRBAM
- Ab + + --------> + + CRBAM-G6PD
CRBAM-G6PD AbCRBAM-G6PD (active)
(INHIBITED)
glucose-6-phosphate CRBAM-G6PD 6-phosphogluconolactone
<-------------
- + -------------> +
NAD+ NADH (absorbs @ 340 nm)
Where: Ab = Anticarbamazepine antibody
CRBAM = Carbamazepine
CRBAM-G6PD = Carbamazepine - glucose-6-phosphate
dehydrogenase conjugate
The concentration of carbamazepine determines the amount of carbamazepine glucose-6-phosphate dehydrogenase conjugate that is bound to anticarbamazepine antibody. The unbound conjugate catalyzes the oxidation of glucose-6-phosphate with the simultan- eous reduction of NAD+ to NADH more rapidly than does the bound conjugate. The rate of increase of absorbance at 340 nm due to the increase in NADH is related to the carbamazepine concen- tration by means of a standard curve, or mathematical function
Clinical significance
- carbamazepine is used in the treatment of
- generalized tonic-clonic seizures
- partial seizures
- partial-complex seizures
- pain associated with trigeminal neuralgia
- after oral administration, carbamazepine is rapidly absorbed but shows wide dual variability
- toxicity associated with excessive carbamazepine is characterized by
- adverse effects at therapeutic concentrations include
- development of an urticarial rash (which usually disappears upon discontinuation of the drug)
- suppression of hematopoiesis
- SIADH
Specimen
Patient preparation: No special patient preparation is required.
Plasma can be used. Collect sample in a green top vacutainer & centrifuge specimen. Serum is the specimen of choice. Serum samples can be collected in a red top vacutainer or red top microtainer. Serum samples can be stored at room temperature for several hours. If frozen at -20C, samples containing carbamazepine is stable for at least 1(one) year. Hemolysis & icterus do not interfere with this method.
Minimum sample size 0.6 milliliters:with an optimum size of 1.5 milliliters or larger.
More general terms
More specific terms
Additional terms
Component of
References
- ↑ Kaplan, L., & Pesce, A., Clinical Chemistry:theory, analysis, & correlation, C. V. Mosby Co., St. Louis, MO., 1984, pp. 1340.
- ↑ Tietz, N., Fundamentals of Clinical Chemistry, 3rd edition W. B. Saunders Co., Philadelphia, 1987, pp. 854.
- ↑ Tietz, N., Textbook of Clinical Chemistry, W. B. Saunders Co., Philadelphia, 1986, pp. 1634, 1635-1636.
- ↑ ACA IV Discrete Clinical Analyzer Instrument Manual, Volume 1:Operation, DuPont Company, Wilmington, Delaware, 1984.
- ↑ ACA IV Discrete Clinical Analyzer Instrument Manual, Volume 3:Chemistry, DuPont Company, Wilmington, Delaware, 1984.
- ↑ Package Insert, EMIT AED Calibrators, Syva Company, Palo Alto, CA.
- ↑ Carbamazepine Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090260.jsp
- ↑ Panel of 3 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0090615.jsp
- ↑ Mini Panel of 2 tests: Carbamazepine, Total . Carbamazepine 10-11 Epoxide Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0092211.jsp