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Principle: | Clinical Significance: | Specimen: | Materials: | Reagents: | Survey Samples: | Standardization: | Procedure: | Limitations: | Results Derivation: | Expected Result(s) | Quality Control: | Legal Alcohol | References:

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Ethanol; Beckman DxC600

I. Principle:

Alcohol reagent is used to measure ethyl alcohol concentration by an enzymatic rate method. In the reaction, alcohol dehydrogenase (ADH) catalyzes the oxidation of ethanol to acetaldehyde with the concurrent reduction of nicotinamide adenine dinucleotide (NAD) to NADH.

II. Clinical Significance:

Ethanol (ethyl alcohol) is a CNS depressant. Testing for alcohol is common in medical/legal cases concerning toxic or abused substances. Alcohol can be lethal by itself or can contribute to accidents of all types. Measurements obtained are used in the diagnosis and treatment of alcohol intoxication and poisoning.

III. Specimen:

  1. Legal Specimens:
    Warning: Alcohol should not be used to swab the venipuncture site.
    Performed on the DxC600 at MMC. Finley does not perform legal alcohol analysis.
    1. Whole blood collected in EDTA, heparin, or fluoride is the specimen of choice. Sample pretreatment is required. Refer to the Procedure section.
    2. Urine may be used. If the urine specimen is for legal cases involving operating a motor vehicle while intoxicated (OWI), it is recommended that the bladder is completely emptied and the sample collected ½ hour later. Turbid specimens should be centrifuged.
  2. Medical specimen:
    Warning: Alcohol should not be used to swab the venipuncture site.
    Serum, heparin, EDTA or sodium fluoride plasma is acceptable for analysis. Specimens must be kept sealed. Samples should be analyzed without delay and immediately after opening the tube.
    1. Hemolysis: Grossly hemolyzed specimens should be handled like whole blood specimens. Refer to the Procedure section.
    2. Lipemia: No significant interference.
    3. Fasting: Not required.
    4. Icteria: No significant interference.
  3. Drugs of Abuse Ethanol Screen:
    Urine; centrifuge cloudy or turbid urine samples prior to analysis.
  4. Specimens should be analyzed without delay and immediately after opening the tube. If specimens cannot be analyzed immediately, they should be stored, unopened, at 2 - 8°C.

IV. Materials:

  1. 13 x 100 mm test tubes with caps and skimmers (plastic or glass)
  2. 400 µl Rainin pipette
  3. Refer to the “DxC600, Beckman Coulter; Operate” procedure.

V. Reagents:

  1. Beckman alcohol Kit (Beckman Coulter #474947)
    1. Store at 2 - 8°C. The reagent is stable until expiration date on the label.
    2. Once opened, the reagent is stable for 60 days unless expiration date is exceeded.
  2. Synchron® Systems ETOH Calibrators (Beckman Coulter #474994):
    1. No preparation required.
    2. Store at 2 - 8°C. The reagent is stable until expiration date on the label.
  3. 6.0% Trichloroacetic Acid:
    1. Dissolve 6.0 g of Trichloroacetic Acid in 100 ml of Type I H2O.
    2. Stable at room temperature.
  4. Beckman Ammonia/Alcohol Controls (Beckman Level 1 #465990, Level 2 #456993)
    1. Store unopened bottles at 2 - 8°C. Once opened, bottles should be stored at 2 - 8°C and are stable for 30 days.
    2. Mix the contents by gently swirling before dispensing and then return the bottles to the refrigerator immediately.
  5. Beckman Ammonia/Alcohol Controls (Beckman 3 #465996)
    1. Store unopened bottles at 2 - 8°C. Once opened, bottles should be stored at 2 - 8°C and are stable for 30 days.
    2. Mix the contents by gently swirling before dispensing and then return the bottles to the refrigerator immediately.
  6. Type I H2O

VI. Survey Samples:

  1. Order an Ethanol in CLICS on a test patient for each survey sample and pre-accession with an accession number starting with AL followed by the sample ID number.
    Example: Survey samples ID numbers are 01, 02, 03, etc.; pre-accession them as AL01, AL02 and AL03 respectively when entering the Ethanol orders through CLICS Order Registration.
  2. When the test is complete, results will be transmitted to CLICS. Release the results from the Interfaced Instrument Result Review Release screen.
  3. Print the result from CLICS Web Inquiry.
  4. The result will be in mg/dl, which is the unit of measure used when reporting the survey results.

VII. Standardization:

  1. Refer to the “DxC600, Beckman Coulter; Operate” procedure for calibration instructions.
  2. Refer to the Quality Control section.

VIII. Procedure:

  1. Legal Whole Blood sample preparation:
    All whole blood samples must be run through the precipitation step prior to analysis. A 1:3 dilution is prepared in order to align with the dilution performed on proficiency testing samples.
    1. Whole blood specimens must be mixed 3-5 minutes before testing.
    2. Label two 13 x 100 mm test tubes for each patient sample.
    3. Pipette 800 µl of 6.0% Trichloroacetic Acid to each tube using the 400 µl pipette and reverse pipetting technique.
    4. Pipette 400 µl of well-mixed whole blood sample into the Trichloroacetic Acid using forward-rinse pipetting technique. Cap tightly.
    5. Vortex for 20 seconds to mix. Centrifuge the tubes for 5 minutes at a minimum of 1500 rcf.
    6. Tubes must remain tightly capped until testing.
    7. When testing is ready to begin, uncap each tube and insert a serum skimmer to separate the supernatant from the sediment. Allow at least 1/8 inch between the filter tip of the skimmer and the surface of the sediment.
      Note: The skimmed supernatant will be brownish.
    8. Transfer approximately a 200 µl aliquot from each tube into appropriately labeled sample cups.
    9. Program a dilution factor of 3.
    10. The correct result will be printed.
  2. Medical plasma sample preparation:
    No sample preparation required.
  3. Drug Screen urine sample preparation:
    1. Centrifuge cloudy or turbid urine samples prior to analysis.
    2. No additional sample preparation is required.
  4. Refer to the “DxC600, Beckman Coulter; Operate” procedure for sample programming.

IX. Limitations:

Adulteration of the urine sample may cause erroneous results. A Creatinine assay is run on each Drug of Abuse urine sample tested for ETOH. (These are run on the DxC600 at MMC-DBQ.) Refer to the “Creatinine; Beckman DxC” procedure.

X. Results Derivation:

  1. Results are reported directly in g/dl. Report all results in g/dl.
  2. For whole blood samples: If the duplicate sample results are within the acceptable 5% the second result from duplicate analysis is reported. If the duplicates are not within 5% of each other there is a possibility of carryover and the samples need to be reassayed.
  3. The linear range for the ETOH assay is 0.01 g/dl to 0.50 g/dl.
    Serum, plasma and urine samples with results greater than the upper linear limit must be diluted volumetrically with saline and reassayed. Refer to the "
    Sample and Control Dilution” protocol. While programming the diluted patient sample, the dilution factor must be entered, so the instrument can calculate the corrected result. In addition, a comment must be entered in the “Lab Comment” field of the LIS to document what dilution was performed.
  4. Samples that are less than .03gm/dl, including “OIR Low”, are reported as “Not detected”.
    Note: The analytical range for serum, plasma and urine samples is 0.005 - 0.6 gm/dl. The analytical range for whole blood is 0.01 - 0.6 gm/dl.

XI. Expected Result(s) and /or Critical Values:

  1. Legal Samples:
    The expected Ethanol concentration is “Not detected”. Refer to state code for legal limit.
  2. Medical Samples:
    ”Not detected”.
  3. Drugs of Abuse Ethanol Screen samples:
    ”Not detected”.

XII. Quality Control:

  1. Routine Controls:
    The Beckman Ammonia/Alcohol Level 1 and Level 2 controls must be assayed once every 24 hours that the assay is run and following new reagent calibration.
  2. Criteria for accepting or rejecting a run is stated in the “Quality Control, General” protocol in the Quality Assurance manual.
  3. Analytical Range: (For Instrument Specialist use only.)
    Serum/plasma, urine: 5 - 600 mg/dl
    Treated whole blood: 10 - 700 mg/dl
  4. Calibrator: Ethanol is calibrated using the Synchron Systems ETOH Calibrators.
  5. Calibration Frequency: Calibration is performed with each new reagent cartridge and every 30 days. Calibration is also performed after major maintenance and/or parts replacement.
  6. Calibration Verification: Calibration verification is performed every 6 months and whenever there is major preventative maintenance or replacement of critical parts that may influence test performance, using Trilevel Synchron Ammonia/Alcohol control material. Calibration verification may also be performed when control results reflect an unusual trend or shift.
  7. Control Ranges: Control mean values are obtained from overlap data of new control lot numbers. Ranges are set the Technical Director.

XIII. Legal Alcohol Protocol:

  1. When a legal alcohol is submitted, a Specimen Chain of Custody and Request form should accompany the specimen. If not, have the person submitting the specimen fill out a Specimen Chain of Custody and Request form.
  2. If possible the technologist receiving the legal ethanol should also perform the ethanol test.
  3. When a specimen is submitted by the Medical Examiner, it is treated as a legal specimen.
  4. If the legal ethanol is not assayed the same day received, it is stored in the locked refrigerator.
  5. After analysis the specimen is stored in the locked refrigerator and saved for one year.
  6. The Specimen Chain of Custody and Request form is a 4 section form.
    1. The white copy remains with the specimen.
    2. The yellow copy remains with lab documents.
    3. The pink copy is sent with the final report.
    4. The gold copy is used as a request, and is sent to data entry.
  7. A manila folder is set up for each patient. The instrument printout (primary document) along with the yellow copy of the Specimen Chain of Custody and request form are placed in the manila folder. Any other paper work that pertains to this specimen is also placed in this manila folder. The manila folder is placed in the locked file.

XIV. References:

  1. Beckman Synchron CX Systems Chemistry Information Manual. Beckman Instruments, Inc. Brea, CA. 1992.
  2. Ethanol-570 DCL procedure. December 1992.
  3. Steve Raymond; Dubuque Pathology Associates, 1992.
  4. ETOH Chemistry Information insert. Beckman Coulter; Brea, CA., May 2000.
  5. Synchron Systems Ammonia/Alcohol Controls package insert. Beckman/Coulter. Fullerton, CA. 2003.
  6. Trace ability of Synchron CX Calibrators. Beckman/Coulter. Brea, CA. 2002.
  7. Chemistry Quick Reference. Unicel DxC Clinical Systems. Synchron Lx, Lx:725 Clinical Systems. Beckman Coulter, Inc. Brea, CA. 2005.

 

  1. September 2000 L. McGovern (Revised: for new Beckman Coulter ETOH assay)
  2. August 2004 S. Raymond/L. McGovern (Revised: V.6., VI., XI., XII., language/protocol updated for CMS status)
  3. April 2006 L. McGovern (Revised: for DxC600)
  4. October 2008 L. McGovern (Revised: VI. Survey Results added)
  5. April 2011 L. McGovern, S. Raymond (Revised: VIII.1.C., I.; X.3)

 

Comprehensive Review:

Pathologist:

Technical Director:

 

Interim Review:
September 2010 M. Dato (no changes)
October 2011 K. Moore (Revised: multiqual controls removed)


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