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Interpretive Handbook

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Test 62745 :
Volatile Screen, Chain of Custody, Blood

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Volatile substances in the blood include ethanol, methanol, isopropanol, and acetone. Acetone is generally elevated in metabolic conditions such as diabetic ketoacidosis. Methanol and isopropanol are highly toxic and result from exogenous ingestion.

 

Ethanol is the single most important substance of abuse in the United States. It is the active agent in beer, wine, vodka, whiskey, rum, and other liquors. Ethanol acts on cerebral function as a depressant similar to general anesthetics. This depression causes most of the typical symptoms such as impaired thought, clouded judgment, and changed behavior. As the level of alcohol increases, the degree of impairment progressively increases.

 

In most jurisdictions in the United States, the per se blood level for being under the influence of alcohol (ethanol) for purposes of driving a motor vehicle is 80 mg/dL.

 

Chain of custody is a record of the disposition of a specimen to document who collected it, who handled it, and who performed the analysis. When a specimen is submitted in this manner, analysis will be performed in such a way that it will withstand regular court scrutiny.

Useful For Suggests clinical disorders or settings where the test may be helpful

Detection and quantitation of acetone, methanol, isopropanol, and ethanol in whole blood

 

Quantification of the concentration of ethanol in blood which correlates with the degree of intoxication

 

Evaluation of toxicity to the measured volatile substances

 

Chain of custody is required whenever the results of testing could be used in a court of law. Its purpose is to protect the rights of the individual contributing the specimen by demonstrating that it was under the control of personnel involved with testing the specimen at all times; this control implies that the opportunity for specimen tampering would be limited.

Interpretation Provides information to assist in interpretation of the test results

Toxic concentrations:

-Methanol: > or =10 mg/dL

-Ethanol: > or =400 mg/dL

-Isopropanol: > or =10 mg/dL

-Acetone: > or =10 mg/dL

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test does not detect ethylene glycol.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

METHANOL

Not detected (Positive results are quantitated.)

Toxic concentration: > or =10 mg/dL

 

ETHANOL

Not detected (Positive results are quantitated.)

Toxic concentration: > or =400 mg/dL

 

ISOPROPANOL

Not detected (Positive results are quantitated.)

Toxic concentration: > or =10 mg/dL

 

ACETONE

Not detected (Positive results are quantitated.)

Toxic concentration: > or =10 mg/dL

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1.Langman, LJ, Bechtel L, Holstege CP: Chapter 35: Clinical Toxicology. In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, Edited by CA Burtis, ER Ashwood, DE Bruns. Philadelphia, PA, WB Saunders Co. 2011, pp 1109-1188

2.Goodman and Gilman's The Pharmacological Basis of Therapeutics, 12th edition. Edited by LL Brunton, DK Blumenthal, N Murr, et al, New York, NY, McGraw-Hill, 2011

3. Principles of Forensic Toxicology, Third edition, Edited by B Levine, Washington DC , AACC Press, 2010


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