Sorted By Test Name - Mayo Medical Laboratories

CYAN
8691
GRP
8771
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
derived from vegetables such as brussel sprouts. Significant contact with cyanide can produce blood
concentrations up to 2.0 mcg/mL without side effects. At concentrations of 2.0 mcg/mL to 4.0 mcg/mL,
giddiness, headaches, and hyperpnea are evident. Concentrations >5.0 mcg/mL are potentially lethal.
Normal concentration: or =2.0 mcg/mL
Reference Values:
Normal: or =2.0 mcg/mL
Clinical References: Medical Toxicology, 3rd edition, RC Dart editor. 2004 pp 1162, 1800
Cyclic AMP, Urinary Excretion
Clinical Information: Cyclic AMP functions as an intracellular "second messenger" regulating the
activity of intracellular enzymes or proteins in response to a variety of hormones (eg, parathyroid
hormone). Urinary cyclic AMP is elevated in about 85% of patients with hyperparathyroidism.
Useful For: The differential diagnosis of hypercalcemia An adjunct to serum parathyroid hormone
measurements, especially in the diagnosis of parathyroid hormone resistance states, such as
pseudohypoparathyroidism
Interpretation: Urinary cyclic AMP is elevated in about 85% of patients with hyperparathyroidism
and in about 50% of patients with humoral hypercalcemia of malignancy.
Reference Values:
1.3-3.7 nmol/dL of glomerular filtrate
Clinical References: Aurbach GD, Marx SJ, Spiegel AM: Parathyroid hormone, calcitonin, and the
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