Sorted By Test Name - Mayo Medical Laboratories

LEVE
83140
FLEVO
90333
phenotype) or near absence (severe phenotype) of CD18 and its associated molecules, CD11a and CD11b,
on neutrophils and other leukocytes. CD11c expression also is low in LAD-1. The analytical sensitivity of
the CD11c assay is insufficient to allow interpretation of CD11c surface expression. Therefore, we test
only for expression of CD18, CD11a, and CD11b.
Reference Values:
Normal (reported as normal or absent expression for each marker)
Clinical References: 1. Anderson DC, Springer TA: Leukocyte adhesion deficiency: an inherited
defect in the Mac-1, LFA-1, and p150,95 glycoproteins. Ann Rev Med 1987;38:175-194 2. Corbi AL,
Vara A, Ursa A, et al: Molecular basis for a severe case of leukocyte adhesion deficiency. Eur J Immunol
1992;22:1877-1881 3. Harlan JM: Leukocyte adhesion deficiency syndrome: insights into the molecular
basis of leukocyte emigration. Clin Immunol Immunopathol 1993;67:S16-S24 4. O'Gorman MR, McNally
AC, Anderson DC, et al: A rapid whole blood lysis technique for the diagnosis of moderate or severe
leukocyte adhesion deficiency (LAD). Ann NY Acad Sci 1993;677:427-430 5. Hogg N, Stewart MP,
Scarth SL, et al: A novel leukocyte adhesion deficiency caused by expressed but nonfunctional beta2
integrins Mac-1 and LFA-1. J Clin Invest 1999;103:97-106 6. Kuijpers TW, van Lier RAW, Hamann D,
et al: Leukocyte adhesion deficiency type 1 (LAD/1) variant. J Clin Invest 1997;100:1725-1733
Levetiracetam, Serum
Clinical Information: Levetiracetam is approved for treatment of partial, myoclonic, and tonic-clonic
seizures, and is used off-label for manic states and migraine prophylaxis. Levetiracetam has very
favorable pharmacokinetics with good bioavailability and rapid achievement of steady state. Its hepatic
metabolism is minimal and non-oxidative, making it safe for use with hepatic enzyme inducers or
inhibitors. The major metabolite is a carboxylic acid derivate, which is inactive and accounts for roughly
one quarter of the administered dose. Levetiracetam is excreted renally, with a mean half-life of 7 hours in
adults and slightly less than that in children. Renal dysfunction may warrant therapeutic monitoring
and/or dose adjustment. Given the lack of drug interactions and favorably pharmacokinetics, the primary
uses for therapeutic drug monitoring of levetiracetam are compliance assurance and management of
physiological changes such as puberty, pregnancy, and aging. Toxicities associated with levetiracetam use
include decreased hematocrit and red blood cell count, decreased neutrophil count, somnolence, asthenia,
and dizziness. These toxicities may be associated with blood concentrations in the therapeutic range.
Useful For: Monitoring serum concentration of levetiracetam, particularly in patients with renal
disease Assessing compliance Assessing potential toxicity
Interpretation: Most individuals display optimal response to levetiracetam with serum levels 12 to 46
mcg/mL. Some individuals may respond well outside of this range, or may display toxicity within the
therapeutic range, thus interpretation should include clinical evaluation. Toxic levels have not been well
established. Therapeutic ranges are based on specimen drawn at trough (ie, immediately before the next
dose).
Reference Values:
12.0-46.0 mcg/mL
Clinical References: 1. Patsalos PN, Berry DJ, Bourgeois BF, et al: Antiepileptic drugs-best practice
guidelines for therapeutic drug monitoring: a position paper by the subcommission on therapeutic drug
monitoring, ILAE Commission on Therapeutic Strategies.Epilepsia 2008 Jul;49(7):1239-1276 2.
Johannessen SI, Tomson T: Pharmacokinetic variability of newer antiepileptic drugs: when is monitoring
needed? Clin Pharmacokinet 2006;45(11):1061-1075
Levodopa, Serum/Plasma
Reference Values:
Reporting limit determined each analysis
Steady state during chronic 3 to 8 gram p.o. dose:
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