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

CYAN
8691
Clinical Information: Skin or mucosal tissue from patients with autoimmune bullous diseases,
connective tissue disease, vasculitis, lichen planus, and other inflammatory conditions often contains
bound immunoglobulin, complement, and/or fibrinogen. Biopsy specimens are examined for the
presence of bound IgG, IgM, IgA, third component of complement (C3), and fibrinogen. For your
convenience, we recommend utilizing cascade testing for celiac disease. Cascade testing ensures that
testing proceeds in an algorithmic fashion. The following cascades are available; select the appropriate
1 for your specific patient situation. Algorithms for the cascade tests are available in Special
Instructions. -CDCOM/89201 Celiac Disease Comprehensive Cascade: complete testing including HLA
DQ -CDSP/89199 Celiac Disease Serology Cascade: complete testing excluding HLA DQ
-CDGF/89200 Celiac Disease Comprehensive Cascade for Patients on a Gluten-Free Diet: for patients
already adhering to a gluten-free diet To order individual tests, see Celiac Disease Diagnostic Testing
Algorithm in Special Instructions.
Useful For: Confirming a diagnosis of bullous pemphigoid, cicatricial pemphigoid, variants of
pemphigoid, all types of pemphigus, dermatitis herpetiformis, linear IgA bullous dermatosis, chronic
bullous disease of childhood, epidermolysis bullosa acquisita, porphyria cutanea tarda, bullous eruption
of lupus erythematosus, herpes gestationis, and atypical or mixed forms of bullous disease, systemic
lupus erythematosus, discoid lupus erythematosus, or other variants, vasculitis, lichen planus, and other
inflammatory diseases.
Interpretation: In pemphigus, direct immunofluorescence (IF) testing will show deposition of IgG,
or rarely IgA, and often complement C3 (C3) at the cell surface (intercelluar substances). In bullous
pemphigoid and cicatricial pemphigoid, direct IF study demonstrates deposition of IgG and C3 at the
basement membrane zone (BMZ) in a linear pattern. In cicatricial pemphigoid, a disease uncommonly
associated with circulating anti-BMZ antibodies, direct IF testing is particularly useful. Biopsy from
patients with dermatitis herpetiformis will show IgA concentrated in dermal papillae and/or in a
granular pattern at the BMZ. In lupus erythematosus (LE), there are granular deposits of
immunoglobulin and complement at the BMZ ("lupus band"). A lupus band is typically found in
lesional skin from patients with a variety of forms of LE; similar findings in biopsies of uninvolved
"normal" skin are consistent with systemic LE. Biopsy of early inflammatory purpuric lesions of
vasculitis will show immunoglobulins and/or complement in dermal vessels. The diagnostic value of
direct IF testing is illustrated in the chart Results of IF Testing under Cutaneous Immunofluorescence
Testing in Special Instructions.
Reference Values:
Report includes description and interpretation of staining patterns. See Results of IF Testing* in
Cutaneous Immunofluorescence Testing in Special Instructions.
Clinical References: Immunopathology of the Skin. Edited by EH Beutner, TP Chorzelski, V
Kumar. 3rd Edition. New York, Wiley Medical Publication, 1987
Cyanide, Blood
Clinical Information: Cyanide (hydrocyanic acid, prussic acid) blocks cellular respiration by
binding to and inactivating hemoglobin and enzymes such as cytochrome oxidase having prosthetic
groups containing ferric iron (Fe+++). Cyanide is metabolized rapidly by the liver where it is converted
to thiocyanate. Therapy of hypertensive crisis with nitroprusside (Nipride) results in elevated cyanide
blood concentrations, because the cyano function is transferred from nitroprusside to hemoglobin in the
red cell. Symptoms of cyanide poisoning include giddiness, hyperpnea, headaches, palpitation,
cyanosis, and unconsciousness. Asphyxial convulsions may precede death; death normally ensues
within a few minutes to 3 hours, depending upon the dose. As long as the heart continues to beat, there
is a chance of saving the patient because effective antidotes are available; treatment with sodium nitrite
and sodium thiosulfate can be effective.
Useful For: Monitoring possible exposure to cyanide Establishing cause of death in cyanide
exposure Not useful for monitoring nitroprusside.
Interpretation: Blood concentrations in the average population are as high as 0.2 mcg/mL, mostly
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