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

GANC
80140
GM1B
83189
Ganciclovir, Serum
Clinical Information: Ganciclovir, an analog of acylcovir, demonstrates inhibitory action against
some viruses including herpes virus, cytomegalovirus, and HIV. Therapeutic ranges have not been
well-established for ganciclovir; current ranges are based on typical values seen during ganciclovir
therapy and do not correlate well to toxicity or outcome. Monitoring of ganciclovir serum concentrations
may be most useful in guiding therapy in patients with renal dysfunction. Myelosuppression is the major
dose-limiting side effect of ganciclovir. Valcyte (valganciclovir) is an oral pro-drug of ganciclovir ester. It
is immediately converted to ganciclovir once it enters the bloodstream. The oral dose is designed to
deliver ganciclovir equivalent to intravenous ganciclovir at 5 mg/kg.
Useful For: Monitoring patients on ganciclovir
Interpretation: Serum concentrations of ganciclovir do not correlate well to toxicity or efficacy. Peak
and trough levels provided are representative of typical serum concentrations seen during therapy, but
individual values must be interpreted in conjunction with the clinical status of the individual patient and
the specific characteristics of the infecting microorganism.
Reference Values:
Trough: 1.0-3.0 mcg/mL
Peak: 3.0-12.5 mcg/mL
Clinical References: 1. Perrottet N, Decosterd LA, Meylan P, et al: Valganciclovir in adult solid
organ transplant recipients: paharmacokinetic and pharmacodynamic characteristics and clinical
interpretation of plasma concentration measurements. Clin Pharmacokinet 2009;48(6):399-418 2. Uges D:
Therapeutic and toxic drug concentrations, The International Association of Forensic Toxicologists. Dec
2009. Retrieved 12/09; Available from URL: www.tiaft.org
Ganglioside Antibody Panel, Serum
Clinical Information: Peripheral neuropathies are a group of disorders that results from lesions on
peripheral nerves. Patients with a peripheral neuropathy can have symptoms of weakness, sensory loss,
and/or autonomic dysfunction. The causes of acquired peripheral neuropathies are varied, and include
vitamin deficiencies, metabolic abnormalities, infections, malignancies (paraneoplastic disorders), and
autoimmune diseases. A subset of the autoimmune-mediated peripheral neuropathies is associated with
the presence of circulating autoantibodies that bind to specific gangliosides. Gangliosides are
glycosphingolipids that contain sialic acid residues. Although present in the plasma membranes of many
cell types, gangliosides are particularly abundant in neural tissue. Guillain-Barre syndrome is one class of
autoimmune peripheral neuropathies, and comprises a spectrum of disorders including acute inflammatory
demyelinating polyradiculoneuropathy, acute motor axonal neuropathy, and acute motor and sensory
axonal neuropathy. This class of autoimmune neuropathies is generally characterized by an acute onset.
Although the diagnosis of these disorders is based significantly on clinical evaluation and
electrophysiologic studies, assessment of ganglioside antibodies, particularly against GM1, asialo GM1,
and GD1b, can provide useful information. It is thought that the Guillain-Barre syndrome disorders are
triggered by an infection, which results in production of infection-associated lipooligosaccharide-specific
antibodies. These antibodies subsequently bind to endogenous gangliosides, due to molecular mimicry,
which leads to immune-mediate damage to the peripheral nerves, ultimately resulting in the clinical
symptoms associated with the disorders.(1)
Useful For: Supporting diagnosis of neurological diseases-primarily motor neuron disease and motor
neuropathies
Interpretation: High titers (>1:2,000) have been found only in patients with multifocal motor
neuropathy and not with motor neuron disease. About 30% to 50% of patients with these clinical
syndromes or the pure motor variant of chronic inflammatory demyelinating polyneuropathy have
increased antibody titers. Increased antibody titers, therefore, appear to be a specific but not sensitive
marker of those related disorders. For IgG and IgM antibodies directed against monosialo GM1 and
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