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HelpTest Code QUIN Quinidine, Serum
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.
Useful For
Assessing and adjusting quinidine dosage for optimal therapeutic level
Assessing quinidine toxicity
Method Name
Kinetic Interaction of Microparticles in Solution (KIMS)
Reporting Name
Quinidine, SSpecimen Type
Serum RedSpecimen Minimum Volume
0.25 mL
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 |
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.
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
Method Description
Kinetic interaction of microparticles in solution 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: Quinidine reagent. Roche Diagnostics; 08/2015)
Day(s) Performed
Monday through Saturday
Report Available
Same day/1 to 2 daysSpecimen Retention Time
2 weeksPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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 |
Forms
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.