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

PA
8683
likelihood of allergic disease as opposed to other etiologies and defines the allergens that may be
responsible for eliciting signs and symptoms. The level of IgE antibodies in serum varies directly with
the concentration of IgE antibodies expressed as a class score or kU/L.
Reference Values:
Class IgE kU/L Interpretation
0 Negative
1 0.35-0.69 Equivocal
2 0.70-3.49 Positive
3 3.50-17.4 Positive
4 17.5-49.9 Strongly positive
5 50.0-99.9 Strongly positive
6 > or =100 Strongly positive Reference values
apply to all ages.
Clinical References: Homburger HA: Allergic diseases. In Clinical Diagnosis and Management by
Laboratory Methods. 21st edition. Edited by McPherson RA, Pincus MR. WB Saunders, Publ, New York,
Chapter 53, Part VI, pp. 961-971, 2007
Procainamide, Serum
Clinical Information: Procainamide (PA) is indicated in the treatment of premature ventricular
contractions, ventricular tachycardia, atrial fibrillation, and paroxysmal atrial tachycardia. PA is
contraindicated in patients with complete atrioventricular block. PA is metabolized to an active
metabolite, N-acetylprocainamide (NAPA), with metabolism controlled by genetically determined
enzymes. In patients with normal renal function, fast metabolizers will have a PA:NAPA ratio 2 after 3 hours) are more likely to
develop a positive test for antinuclear antibodies and present with systemic lupus erythematosus-like
symptoms. Patients who have prolonged exposure to procainamide >10.0 mcg/mL or NAPA
concentration >40.0 mcg/mL are very likely to exhibit symptoms of toxicity that are characterized by
hypotension, ventricular fibrillation, widened QRS complex, junctional tachycardia, oliguria, confusion,
nausea, and vomiting. Renal disease, hepatic disease, cardiac failure, and states of low cardiac output
reduce the metabolism and clearance of PA and NAPA. Co-administration of histamine H2 receptor
antagonists, such as cimetidine and ranitidine reduce renal clearance of PA and NAPA resulting in higher
plasma concentrations of each.
Useful For: Monitoring therapy Assessing compliance Evaluating toxicity
Interpretation: Administration of a dose of 50 mg/kg will usually yield the optimal trough
concentration in the range of 4.0 to 8.0 mcg/mL for procainamide and 10.0 to 20.0 mcg/mL for
N-acetylprocainamide.
Reference Values:
PROCAINAMIDE
Therapeutic concentration: 4.0-8.0 mcg/mL
Toxic concentration: >10.0 mcg/mL
N-ACETYLPROCAINAMIDE
Therapeutic concentration: 10.0-20.0 mcg/mL
Toxic concentration: >40.0 mcg/mL
Clinical References: Myerburg RJ, Kessler KM, Kiem I, et al: Relationship between plasma levels
of procainamide, suppression of premature ventricular complexes and prevention of recurrent ventricular
tachycardia. Circulation 1981;64;280-290
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