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ANAP
81157
TTR-associated familial AL is suspected. The structure of TTR in plasma is first determined by MS. Only
the transthyretin (also known as prealbumin) is analyzed for amino acid substitutions. Other proteins
known to be involved in other less common forms of familial amyloidosis are not examined. If no
alterations are detected, gene analysis will not be performed unless requested by the provider for cases in
which the diagnosis is still strongly suspected (to rule-out the possibility of a false-negative by MS). In all
cases demonstrating a structural change by MS, the entire TTR gene will be analyzed by DNA sequence
analysis to identify and characterize the observed alteration (gene mutation or benign polymorphism). For
predictive testing in cases where a familial mutation is known, testing for the specific mutation by DNA
sequence analysis (AMYKM/83705 Amyloidosis, Transthyretin-Associated Familial, Known Mutation,
Blood) is recommended. These assays do not detect mutations associated with non-TTR forms of familial
AL. Therefore, it is important to first test an affected family member to determine if TTR is involved and
to document a specific mutation in the family before testing at risk individuals.
Useful For: Diagnosis of adult individuals suspected of having transthyretin (TTR)-associated familial
amyloidosis
Interpretation: The presence of a structural change in transthyretin (TTR) is suggestive of a gene
mutation that requires confirmation by DNA sequence analysis. A negative result by mass spectrometry
does not rule-out a transthyretin mutation. Mass spectrometric results are falsely negative if the amino
acid substitution does not produce a measurable mass shift for the mutation transthyretin. Approximately
90% of the TTR mutations are positive by MS (see Cautions). After identification of the mutation at the
DNA level, predictive testing for at risk family members can be performed by molecular analysis
(AMYKM/83705 Amyloidosis, Transthyretin-Associated Familial, Known Mutation, Blood).
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Benson MD: The hereditary amyloidoses. Best Pract Res Clin Rheumatol
2003;17:909-927 2. Shimizu A, Nakanishi T, Kishikawa M, et al: Detection and identification of protein
variants and adducts in blood and tissues: an application of soft ionization mass spectrometry to clinical
diagnosis. J Chromatogr B Analyt Technol Biomed Life Sci 2002 Aug 25;776(1):15-30 3. Lim A,
Prokaeva T, McComb ME, et al: Characterization of transthyretin variants in familial transthyretin
amyloidosis by mass spectrometric peptide mapping and DNA sequence analysis. Anal Chem 2002 Feb
15;74(4):741-751 4. Boston University School of Medicine, BUSM. Mass Spectrometry Resource.
Available from URL: bumc.bu.edu/Dept/Home.aspx?DepartmentID=354 5. Eneqvist T, Sauer-Eriksson
AE: Structural distribution of mutations associated with familial amyloidotic polyneuropathy in human
transthyretin. Amyloid 2001;8:149-168
Anaplasma phagocytophilum (Human Granulocytic
Ehrlichiosis) Antibody, Serum
Clinical Information: Human granulocyte ehrlichiosis (HGE) is a zoonotic infection caused by a
rickettsia-like agent. The infection is acquired by contact with Ixodes ticks carrying the HGE agent. The
deer mouse is the animal reservoir and, overall, the epidemiology is very much like that of Lyme disease
and babesiosis. HGE is most prevalent in the upper Midwest and in other areas of the United States that
are endemic for Lyme disease. Since its first description in 1994, there have been approximately 50 cases
of HGE described in the upper Midwest. The cellular target in HGE cases is the neutrophil. The
organisms exist in membrane-lined vacuoles within the cytoplasm of infected host cells. Ehrlichial
inclusions, called morulae, contain variable numbers of organisms. Single organisms, wrapped in vacuolar
membranes have also been observed in the cytoplasm. Ehrlichia species occur in small electron-dense and
large electron-lucent forms, but a clear life cycle has not been elucidated. Diagnosis of human ehrlichiosis
has been difficult because the patient's clinical course is often mild and nonspecific, including fever,
myalgias, arthralgias, and nausea. This is easily confused with other illnesses such as influenza or other
tickborne zoonoses such as Lyme disease, babesiosis, and Rocky Mountain spotted fever. Clues to the
diagnosis of ehrlichiosis in a patient with an acute febrile illness after tick exposure include laboratory
findings of leukopenia or thrombocytopenia and elevated serum aminotransferase levels. However, these
findings may also be present in patients with Lyme disease or babesiosis.
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