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Epic Code LAB1230569 Quinidine, Serum

Additional Codes

Mayo Code: QUIN

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Assessing and adjusting quinidine dosage for optimal therapeutic level

 

Assessing quinidine toxicity

Specimen Type

Serum Red


Specimen Required


Collection Container/Tube: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial within 2 hours of collection.


Laboratory Test Directory Note:

COLLECTION NOTE: Volumes listed are in serum or plasma, draw approximately 2 1/2 times the requested volume in whole blood.

Specimen Minimum Volume

0.25 mL

Forms

If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 14 days
  Frozen  28 days
  Ambient  14 days

Reject Due To

Gross hemolysis Reject

Cautions

No significant cautionary statements

Clinical Information

Quinidine is indicated for atrial fibrillation and flutter, and life-threatening ventricular arrhythmia. Optimal serum concentrations are in the range of 2.0 to 5.0 mcg/mL, with toxicity apparent at levels of 6.0 mcg/mL or higher. Symptoms of toxicity (cinchonism) include tinnitus, light-headedness, premature ventricular contractions, and atrioventricular block. Gastrointestinal distress is a frequent side effect that becomes more severe and is associated with nausea and vomiting at higher drug concentrations.

 

The half-life of quinidine is 6 to 8 hours. Physiologic processes that generally reduce hepatic metabolism and renal clearance increase serum quinidine levels, while comedication with cytochrome p450 (CYP)-enzyme inducers enhances clearance and results in lower blood concentrations.

Method Name

Kinetic Interaction of Microparticles in Solution (KIMS)

Report Available

Same day/1 to 2 days

Reporting Name

Quinidine, S

Reference Values

Therapeutic: 2.0-5.0 mcg/mL

Critical value: ≥6.0 mcg/mL

Interpretation

Optimal response to quinidine occurs when the serum level is between 2.0 to 5.0 mcg/mL.

Method Description

Kinetic interaction of microparticles in solution (KIMS) as measured by changes in light transmission. The assay is a homogeneous immunoassay based on the principle of measuring changes in scattered light or absorbance which result when activated microparticles aggregate. The microparticles are coated with quinidine and rapidly aggregate in the presence of a quinidine antibody solution. When a sample containing quinidine is introduced, the aggregation reaction is partially inhibited, slowing the rate of the aggregation process. Antibody bound to sample drug is no longer available to promote microparticle aggregation, and subsequent particle lattice formation is inhibited. Thus, a classic inhibition curve with respect to quinidine concentration is obtained, with the maximum rate of aggregation at the lowest quinidine concentration. By monitoring the change in scattered light or absorbance, a concentration-dependent curve is obtained.(Package insert: Roche Quinidine reagent. Roche Diagnostics; 08/2015)

Day(s) Performed

Monday through Saturday

Clinical Reference

1. Milone MC, Shaw LM: Therapeutic drugs and their management. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, Elsevier; 2018: 800-831

2. Brunton LL, Hilal-Dandan R, Knollmann BC, eds. Goodman and Gilman's: The Pharmacological Basis of Therapeutics. McGraw-Hill; 2018

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

80194

LOINC Code Information

Test ID Test Order Name Order LOINC Value
QUIN Quinidine, S 6694-4

 

Result ID Test Result Name Result LOINC Value
8302 Quinidine, S 6694-4