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FVPA
81771
patients with uveal melanoma are quite high (approximately 50%) and are due to metastatic disease.(2)
Identifying patients likely to develop metastasis is critical for establishing patient prognosis. Previous
studies have demonstrated that monosomy 3 is highly correlated with the development of metastatic
disease in patients with uveal melanoma.(1,3)
Useful For: As an aid to prognosis in patients with uveal melanoma
Interpretation: A neoplastic clone is detected when the percent of cells with an abnormality exceeds
the normal reference range for any given probe. A positive result is consistent with monosomy 3 and a
higher risk for metastatic disease in uveal melanoma patients. A negative result suggests the absence of
monosomy 3.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Tschentscher F, Prescher G, Horsman DE, et al: Partial deletions of the long
and short arm of chromosome 3 point to two tumor suppressor genes in uveal melanoma. Cancer Res
2001 April 15;61(8):3439-3442 2. Prescher G, Bornfeld N, Hirche H, et al: Prognostic implications of
monosomy 2 in uveal melanoma. Lancet 1996 May 4;347(9010):1222-1225 3. Cross NA, Ganesh A,
Parpia M, et al: Multiple locations on chromosome 3 are the targets of specific deletions in uveal
melanoma. Eye 2006 Apr;20(4):476-481 4. Parrella P, Fazio VM, Gallo AP, et al: Fine mapping of
chromosome 3 in uveal melanoma: identification of a minimal region of deletion on chromosomal arm
3p25.1-p25.2. Cancer Res 2003 Dec 1;63(23):8507-8510
Valproic Acid, Free and Total, Serum
Clinical Information: Valproate (Depakote/Depakene valproic acid) is an effective medication for
absence seizures, generalized tonic-clonic seizures, and partial seizures, when administered alone or in
conjunction with other antiepileptic agents. The valproic acid that circulates in blood is 85% to 90%
protein-bound under normal circumstances. In uremia or during concomitant therapy with other drugs that
are highly protein-bound (such as phenytoin), valproic acid is displaced from protein, resulting in a higher
free fraction of the drug circulating in blood. Since neurologic activity and toxicity of valproic acid are
directly related to the unbound fraction of drug, adjustment of dosage based on knowledge of the free
valproic acid concentration may be useful in the following situations: concomitant use of highly
protein-bound drugs (usually >80% bound), hypoalbuminemia, pregnancy, renal or hepatic failure, and in
the elderly. In these situations, the total valproic acid concentration in the blood may underestimate the
disproportionately higher free valproic acid fraction.
Useful For: Monitoring therapy Assessing compliance Evaluating potential toxicity
Interpretation: The generally acceptable range for total valproic acid used as a reference to guide its
therapy is 40 mcg/mL to 100 mcg/mL. The corresponding range of free valproic acid concentration for
clinical reference is 4 mcg/mL to 15 mcg/mL. Low free valproic acid concentration relative to these
ranges may suggest inadequate dosing, while, a high free valproic acid concentration may be associated
with toxic effects. Because the concentration of valproic acid fluctuates considerably depending on the
time from last dose, interpretation of the clinical significance of the valproic acid concentration must take
into consideration the timing of the blood specimen. For this reason, 2 collections are sometimes made to
assess the trough and peak concentrations.
Reference Values:
TOTAL
Therapeutic concentration: 40 (trough)-100 (peak) mcg/mL
Toxic concentration: > or =120 mcg/mL
FREE
Therapeutic concentration: 4-15 mcg/mL
Toxic concentration: >15 mcg/mL
Clinical References: 1. Cloyd JC, Fischer JH, Kriel RL, Kraus DM: Valproic acid pharmacokinetics
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