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Test Code QUIND Quinidine, Serum

Important Note

ASANTE order code is QUINB

Useful For

Assessing and adjusting dosage for optimal therapeutic level

 

Assessing toxicity

Method Name

Kinetic Interaction of Microparticles in Solution (KIMS)

Reporting Name

Quinidine, S

Specimen Type

Serum Red


Specimen Required


Container/Tube: Red top

Specimen Volume: 0.5 mL

Collection Instructions: Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.


Specimen Minimum Volume

0.25 mL

Specimen Stability Information

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

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

NA

Icterus

NA

Other

Serum gel tube

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 ≥6.0 mcg/mL. Symptoms of toxicity (cinchonism) include tinnitus, light-headedness, premature ventricular contractions, and atrioventricular block. Gastrointestinal distress is a frequent side effect, which becomes more severe and is associated with nausea and vomiting at higher drug concentrations.

 

The half-life of quinidine is 6 to 8 hours, and the drug lacks any significant active metabolites. 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.

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.

Cautions

No significant cautionary statements.

Clinical Reference

1. Valdes R Jr, Jortani SA, Gheorghiade M: Standards of laboratory practice: cardiac drug monitoring. National Academy of Clinical Biochemistry. Clin Chem 1998;44(5):1096-1109

2. Qunidine. In Physician's Desk Reference (online) Accessed November, 2009

Method Description

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 rapidlyaggregate 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 Diagnostic Corp, Indianapolis, IN)

Day(s) and Time(s) Performed

Monday through Sunday; Continuously

Analytic Time

Same day/1 day

Specimen Retention Time

1 week

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

80194

LOINC Code Information

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

 

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