Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

FELBA
80782
porphyrins in the stool, is very sensitive, and provides quantitative results.
Useful For: Colorectal cancer screening Screening for gastrointestinal bleeding
Interpretation: This is a quantitative assay but results are reported qualitatively as negative or
positive for the presence of fecal occult blood; the cutoff for positivity is 100 ng/mL hemoglobin. The
following comments will be reported with the qualitative result for patients >17 years: -Positive results;
further testing is recommended if clinically indicated. This test has 97% specificity for detection of
lower gastrointestinal bleeding in colorectal cancer. -Negative results; this test will not detect upper
gastrointestinal bleeding; HQ/9220 HemoQuant, Feces test should be ordered if clinically indicated.
Reference Values:
Negative
This test has not been validated in a pediatric population, results should be interpreted in the context of
the patient's presentation.
Clinical References: 1. Levin B, Lieberman DA, McFarland B, et al: Screening and Surveillance
for the Early Detection of Colorectal Cancer and Adenomatous Polyps, 2008: A Joint Guideline from
the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the
American College of Radiology. CA Cancer J Clin 2008;58:130 2. Whitlock EP, Lin JS, Liles E, et al:
Screening for colorectal cancer: a targeted, updated systematic review for the U.S. Preventive Services
Task Force. Ann Intern Med 2008;149:638 3. Hol L, Wilschut JA, van Ballegooijen M, et al: Screening
for colorectal cancer: random comparison of guaiac and immunochemical faecal occult blood testing at
different cut-off levels. Br J Cancer 2009;100:1103 4. Levi Z, Rozen P, Hazazi R, et al: A quantitative
immunochemical fecal occult blood test for colorectal neoplasia. Ann Intern Med 2007;146:244 5.
Tannous B, Lee-Lewandrowski E, Sharples C, et al: Comparison of conventional guaiac to four
immunochemical methods for fecal occult blood testing: implications for clinical practice in hospital
and outpatient settings. Clin Chem Acta 2009;400:120-122
Felbamate (Felbatol), Serum
Clinical Information: Felbamate is an anticonvulsant drug approved for treatment of partial
seizures with or without secondary generalization in persons >14 years of age. It is also approved for
Lennox-Gastout syndrome in children >2 years of age. Felbamate is well absorbed (>90%) and is
metabolized by the hepatic cytochrome P450 system. Metabolites lack anticonvulsant activity. The
elimination half-life of felbamate ranges from 13 to 23 hours. Optimal response to felbamate is seen
with serum concentrations between 30 mcg/mL to 60 mcg/mL. Patients who are elderly or have renal
dysfunction may require reduced dosing; felbamate should not be given to individuals with hepatic
disease. Toxicity can be severe, including life-threatening aplastic anemia or liver failure, but no
defined toxic concentration has been established. Coadministration of felbamate increases the
concentration of phenytoin and valproic acid, decreases carbamazepine concentration, and increases
carbamazepine-10,11-epoxide (its active metabolite). Conversely, coadministration of phenytoin or
carbamazepine causes a decrease in felbamate concentration.
Useful For: Determining whether a poor therapeutic response is attributable to noncompliance or
lack of drug effectiveness Monitoring changes in serum concentrations resulting from interactions with
coadministered drugs such as barbiturates and phenytoin
Interpretation: Optimal response to felbamate is associated with serum concentrations of 30
mcg/mL to 60 mcg/mL. Toxic serum concentrations for felbamate have not been established.
Reference Values:
30.0-60.0 mcg/mL
Clinical References: 1. Johannessen, SI, Tomson, T: Pharmacokinetic Variability of Newer
Antiepileptic Drugs: When is Monitoring Needed? Clin Pharmacokinet 2006; 45 (11): 1061-10752.
Schmidt D: Felbamate: successful development of a new compound for the treatment of epilepsy.
Epilepsia 1996;34(Suppl 7):S30-S33 2. Patsalos PN: Antiepileptic drugs--best practice guidelines for
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