Download Prepared By - Beckman Coulter

Procedure:
Quinidine
OSR4Q229
This procedure is valid for the following chemistry analyzers:

AU400/AU400e

AU640/AU640e

AU480

AU680

AU600

AU2700/AU5400
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Page 1 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
PRINCIPLE:
Quinidine is a cardiac anti-arrhythmic medication used to correct
disturbances in the heart’s rhythm. It is used in the treatment of atrial
premature contraction, ventricular tachycardia, and in prophylactic
treatment following myocardial infarction.
Monitoring serum quinidine concentrations, along with careful clinical
assessment, is the most effective means of achieving an optimum antiarrhythmic effect and reducing the risk of toxicity for the following reasons:

Serum quinidine concentrations correlate better with pharmacologic
activity than does dosage.1,2

The quinidine dosage required to control cardiac arrhythmias varies
substantially in different patients and in the same patient at different
times. These variations are due to differences in absorption and
metabolism and to the influences of disease states and coadministered
drugs.1-3

Quinidine is safe and effective only in a narrow range of serum
concentrations. 1-3

The symptoms of serious quinidine toxicity can mimic those of an
ineffectively controlled cardiac disorder.1
Methods historically used to monitor serum quinidine concentrations include
spectroscopic assay, chromatographic assay and immunoassay.1,2,4
INTENDED USE:
The Emit® 2000 Quinidine Assay is intended for use in the quantitative
analysis of quinidine in human serum or plasma. These reagents are
designed for use on multiple Beckman Coulter AU Analyzers.
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All printed copies are considered to be copies of the electronic original.
Page 2 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
METHODOLOGY:
The Emit® 2000 Quinidine Assay is a homogeneous enzyme immunoassay
technique used for the analysis of specific compounds in biological fluids.4,5
The assay is based on competition between drug in the sample and drug
labeled with the enzyme glucose-6-phosphate dehydrogenase (G6PDH) for
antibody binding sites. Enzyme activity decreases upon binding to the
antibody, so the drug concentration in the sample can be measured in terms
of enzyme activity. Active enzyme converts oxidized nicotinamide adenine
dinucleotide (NAD) to NADH, resulting in an absorbance change that is
measured spectrophotometrically. Endogenous serum G6PDH does not
interfere because the coenzyme functions only with the bacterial (Leuconostoc
mesenteroides) enzyme employed in the assay.
SPECIMEN:
PATIENT / SAMPLE PREPARATION:
No special preparation for the patient is required. The patient’s clinical
condition and dosage regimen may influence the sample collection time.
Pharmacokinetic factors influence the correct time of sample collection
after the last drug dose. These factors include dosage form, mode of
administration, concomitant drug therapy, and biological variations
affecting drug disposition.1-3
SAMPLE COLLECTION TIME:
Measure the steady-state serum concentration representing the trough
level just before the next scheduled dose.
Additional instructions for preparation as designated by this laboratory:
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All printed copies are considered to be copies of the electronic original.
Page 3 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
TYPE:
Serum or plasma is the recommended specimen. Whole blood cannot be
used. The anticoagulants heparin, citrate, oxalate, and EDTA have been
tested and may be used with this assay.
Some sample dilution may occur when samples are collected in tubes
containing citrate anticoagulant. The amount of dilution and the possible
need to correct for it should be considered when interpreting assay results
for these samples.
Additional type conditions as designated by this laboratory:
HANDLING CONDITIONS:
Store the serum or plasma refrigerated at 2-8°C. For transporting,
maintain the sample temperature at 2-8°C. Samples can be stored
refrigerated at 2-8°C for up to 7 days or stored frozen (-20°C) for up to 1
month.
Samples that contain particulate matter, fibrous material, or gel-like
masses; appear unusual; or are frozen require preparation. Use the
following instructions to prepare such samples:
1. If sample is frozen, thaw completely at a room temperature of 1525°C.
2. Vigorously mix all samples: Vortex for at least 30 seconds.
3. Centrifuge sample at > 2000 rpm for 15 minutes.
4. Collect a sample from the middle portion of the specimen. Avoid
collecting lipids from the top portion or particulate matter from the
bottom portion.
Human serum or plasma samples should be handled and disposed of as if
they were potentially infectious.
© Beckman Coulter, Inc. 2010
All printed copies are considered to be copies of the electronic original.
Page 4 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
Additional handling conditions as designated by this laboratory:
EQUIPMENT AND MATERIALS:
EQUIPMENT:
Beckman Coulter AU400/AU400e, AU480, AU600, AU640/AU640e,
AU680, AU2700, and AU5400 analyzers.
MATERIALS:
Emit® 2000 Quinidine Assay
Antibody/Substrate Reagent 1 — mouse monoclonal antibodies
reactive to quinidine, glucose-6-phosphate, nicotinamide adenine
dinucleotide, preservatives, and stabilizers
Enzyme Reagent 2 — quinidine labeled with glucose-6-phosphate
dehydrogenase, Tris buffer, preservatives, 0.1% sodium azide and
stabilizers
Reagent storage location in this laboratory:
Test tubes 12 -16 mm in diameter or sample cups
(Cat No. AU1063).
Storage location of test tubes or sample cups in this laboratory:
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All printed copies are considered to be copies of the electronic original.
Page 5 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
Emit® 2000 Quinidine Calibrator
(Cat No. 4Q109)
The Emit 2000 Quinidine Calibrators contain the following stated
quinidine concentrations: 0 g/mL, 0.5 g/mL, 1.0 g/mL, 2.0 g/mL,
4.0 g/mL, 8.0 g/mL. The calibrator kit is sold separately.
Preparation
The Emit 2000 Quinidine reagents and calibrators are packaged in a
ready to use liquid form and may be used directly from the
refrigerator. Close the calibrator vials when not in use. Caps must
always be replaced on the original containers.
Note: Reagents 1 and 2 are provided as a matched set. They
should not be interchanged with components of kits with different
lot numbers.
Precautions:
1. The Emit® 2000 Quinidine Assay and Calibrators are for in vitro
diagnostic use.
2. Reagent 1 contains non-sterile mouse monoclonal antibodies.
3. Do not use the reagents or calibrators after the expiration date.
4. Assay components contain sodium azide, which may react with lead
and copper plumbing to form highly explosive metal azides. If
waste is discarded down the drain, flush it with a large volume of
water to prevent azide buildup. Dispose of properly in accordance
to local regulations.
5. This kit contains streptomycin sulfate. Please dispose of
appropriately.
Storage Requirements:
Any reagents not loaded in the reagent refrigerator on the analyzer or
any calibrators not in use should be stored at 2-8°C (36-46°F), upright,
© Beckman Coulter, Inc. 2010
All printed copies are considered to be copies of the electronic original.
Page 6 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
and with caps tightly closed. Do not freeze reagents or calibrators or
expose them to temperatures above 32°C.
Unopened reagents and calibrators are stable until the expiration date
printed on the label if stored as directed. Refer to Assay Methodology
Sheets for additional on-board stability information.
Improper storage of reagents or calibrators can affect assay
performance. Stability depends on handling reagents or calibrators as
directed.
Additional storage requirements as designated by this laboratory:
Indications of Deterioration:
Discoloration (especially yellowing) of the reagents or calibrators,
visible signs of microbial growth, turbidity, or precipitation in reagent
or calibrator may indicate degradation and warrant discontinuance of
use.
PERFORMANCE PARAMETERS:
The following performance characteristics represent total system
performance and should not be interpreted to refer only to reagents. Studies
were performed on the Beckman Coulter AU analyzer series. Results may
vary due to analyzer-to-analyzer differences.
PRECISION
Within run precision was calculated by running twenty replicates of each
level of a tri-level control. Total precision was calculated according to
Clinical and Laboratory Standards Institute (CLSI EP5-A) using data
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All printed copies are considered to be copies of the electronic original.
Page 7 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
collected from controls run in duplicate twice daily over twenty days
(N=80).
Within-Run Precision
Total Precision
Level 1
Level 2
Level 3
Level 1
Level 2
Level 3
Mean (µg/mL)
1.45
3.28
4.67
1.39
3.34
4.68
CV %
2.9
3.4
3.0
8.5
6.7
9.3
COMPARISON
Samples from patients were analyzed using the Emit® 2000 Quinidine
Assay on the TDx analyzer and the AU600. The comparative analysis is
given below.
Slope
1.02
Intercept (g/mL)
-0.06
Mean (g/mL)
TDx
AU600
2.85
2.86
Correlation Coefficient
0.98
Number of Samples
53
CALIBRATION:
Perform a multi-point calibration (5AB) using a water blank (blue rack) and
the Emit® 2000 Quinidine Calibrators: 0.5, 1.0, 2.0, 4.0, 8.0. Calibration
parameters are set to prepare the calibration curve. Refer to analyzer User’s
Guide or Analyzer Specific Protocol sheets for analyzer settings.
© Beckman Coulter, Inc. 2010
All printed copies are considered to be copies of the electronic original.
Page 8 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
CALIBRATION STABILITY
Studies have shown the median calibration stability to be at least 14 days.
Recalibrate as indicated by control results or with a new lot of reagent.
Calibration stability may vary from laboratory to laboratory depending on
the following: handling of reagents, maintenance of analyzer, adherence to
operating procedures, establishment of control limits, and verification of
calibration.
Note: When using a new set of reagents with the same lot number,
validate the system by assaying controls.
QUALITY CONTROL:
During operation of the Beckman Coulter AU analyzer multi-level controls
should be tested in every run or a minimum of once a day. Controls should be
performed after calibration, with each new set or lot of reagent, and after
specific maintenance or troubleshooting steps described in the appropriate
User’s Guide. Quality control testing should be performed in accordance with
regulatory requirements and individual laboratory’s standard procedures. If
more frequent verification of test results is required by the operating
procedures within your laboratory, those requirements should be met.
PARAMETERS
A complete list of test parameters and operating procedures can be found in
the appropriate User’s Guide and at www.beckmancoulter.com.
CALCULATIONS:
Results are calculated automatically by the analyzer. No additional
manipulation of data is required.
This assay uses Math Model No. 1.
To convert from g/mL to mol/L quinidine, multiply by 3.08.
© Beckman Coulter, Inc. 2010
All printed copies are considered to be copies of the electronic original.
Page 9 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
REPORTING RESULTS:
REFERENCE RANGES:
Clinicians should be aware of the differences among the various analytical
methods used to measure quinidine and how these differences may affect
the range of quinidine concentrations that are defined as therapeutic.
Regardless of the method used to measure quinidine concentrations, the
therapeutic range is variable between patients. Plasma quinidine levels
between approximately 2 and 5 g/mL have commonly been considered
effective.1-4, 8 In all cases, the clinician should carefully consider patient
response and evidence of toxicity along with blood levels in determining
optimal quinidine therapy.
Expected reference ranges in this laboratory:
PROCEDURES FOR ABNORMAL RESULTS
The laboratory must define procedures to be used in reporting high
concentration (toxic) results to the patient’s physician.
Abnormal results are flagged by the listed analyzers according to the
normal values entered by the user into the analyzer parameters.
REPORTING FORMAT:
Results are automatically printed for each sample in g/mL at 37°C.
Interpretation of Results
The factors that can influence the relationship between the quinidine
serum or plasma concentrations and clinical response include the type
and severity of arrhythmia, liver function, kidney function, general
state of health, and use of other drugs.1-3
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All printed copies are considered to be copies of the electronic original.
Page 10 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
The concentration of quinidine in serum or plasma depends on the
time of the last drug dose; mode of administration; concomitant drug
therapy; sample condition; time of sample collection; and individual
variations in absorption, distribution, biotransformation, and
excretion. These parameters must be considered when interpreting
results. 1-3
Additional reporting information as designated by this laboratory:
LIMITATIONS:
The Emit 2000 Quinidine Assay accurately quantitates quinidine
concentrations in human serum or plasma containing 0.5–8.0 g/mL (1.5-25 
mol/L) quinidine.
To estimate quinidine concentrations above the assay range, patient samples
containing more than 8.0 g/mL (25 mol/L) quinidine may be diluted with
one or two parts distilled or deionized water or Emit 2000 Quinidine
Calibrator 0. After diluting the sample, repeat the entire assay sequence and
multiply the results by the dilution factor.
Adulteration of reagents, use of analyzer without appropriate capabilities, or
other failures to follow instructions as set forth in this protocol or the package
insert can affect performance characteristics and stated or implied claims.
INTERFERING SUBSTANCES
No clinically significant interference has been found in samples to which
800 mg/dL hemoglobin, 1000 mg/dL triglycerides, or 30 mg/dL bilirubin
were added to simulate hemolytic, lipemic, or icteric samples.
Dihydroquinidine (DHQ), a constituent of pharmaceutical quinidine
preparations,6,7 has anti-arrhythmic activity and pharmacokinetic
properties similar to those of quinidine.7 DHQ makes a small, but
© Beckman Coulter, Inc. 2010
All printed copies are considered to be copies of the electronic original.
Page 11 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
measurable contribution to the assayed value. Levels of DHQ in serum
are reported to be approximately 5% to 10% of the total quinidine level.6
SENSITIVITY
The sensitivity level of the Emit 2000 Quinidine Assay is 0.25 g/mL.
This level represents the lowest measurable concentration of quinidine
that can be distinguished from 0 g/mL with a confidence level of 95%.
SPECIFICITY
The Emit® 2000 Quinidine Assay measures the total (protein-bound plus
unbound) quinidine concentration in serum or plasma. In addition,
dihydroquinidine (DHQ) makes a small, but measurable, contribution to
the assayed value.
Compounds whose chemical structure or concurrent therapeutic use
would suggest possible cross-reactivity have been tested.
-Desmethylquinidine (DMQ), a minor metabolite of quinidine, crossreacts with this assay.
The compounds listed below do not interfere with the Emit® 2000
Quinidine Assay when tested in the presence of 2.0 g/mL quinidine.
Levels tested were at or above maximum physiological or pharmacological
concentrations.
Compound
Concentration Tested
(g/mL)
Structurally Related Compounds
3-Hydroxyquinidine
5
2-Oxoquinidinone
2
Quinine
20
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All printed copies are considered to be copies of the electronic original.
Page 12 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
Structurally Unrelated Compounds
Clonidine
100
Digoxin
0.1
Disopyramide
100
Furosemide
100
Hydrochlorothiazide
100
Lidocaine
100
Methyldopa
100
N-Acetylprocainamide
100
Procainamide
100
Propranolol
100
Tocainide
100
REFERENCES:
1. Covinsky JO, Conn RD: Quinidine: Therapeutic Use and Serum
Concentration Monitoring. In: Taylor WJ, Finn AL (eds): Individualizing
Drug Therapy: Practical Applications of Drug Monitoring. New York:
Gross, Townsend, Frank, Inc. 1981, vol 3, pp 111-132.
2. Ueda CT. Quinidine. In Evans WE, Shentag JJ, Jusko WJ eds: Applied
Pharmacokinetics: Principles of Therapeutic Drug Monitoring.
Washington: Applied Therapeutics, Inc. 1986, pp 712-734.
3. Bigger JT Jr., Hoffman BF. Antiarrhythmic Drugs. In: Gilman AG, Rall
TW, Nies AS, et al (eds). Goodman and Gilman's The Pharmacological
Basis of Therapeutic, Ed 8. New York: Pergamon Press Inc. 1990, pp 840873.
4. Pincus MR, Abraham NZ Jr. Toxicology and Therapeutic Drug
Monitoring. In: Henry JB ed: Clinical Diagnosis and Management by
Laboratory Methods, Ed 18. Philadelphia: WB Saunders Co. 1991, pp 349–
384.
© Beckman Coulter, Inc. 2010
All printed copies are considered to be copies of the electronic original.
Page 13 of 14
Rev # 1, Dec 31, 10
Procedure:
Quinidine
OSR4Q229
5. Pope E, Huster M: Syva Emit® 2000 Quinidine Assay. Clin Chem 1992;
38(6):338. Abstract.
6. Guentert TW, et al: Determination of quinidine and its major metabolites
by high-performance liquid chromatography. J Chromatogr 1979;162:5970.
7. Ueda CT, et al: Disposition kinetics of dihydroquinidine following
quinidine administration. Res Commun Chem Pathol Pharmacol 1976;
14:215-225.
8. Fattinger K, Vozeh S, Ha HR, et al: Population pharmacokinetics of
quinidine. BR J Clin Pharmacol 1991; 31:279-286.
© Beckman Coulter, Inc. 2010
All printed copies are considered to be copies of the electronic original.
Page 14 of 14
Rev # 1, Dec 31, 10