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HelpTest Code ALCX Ethanol, Chain of Custody, Blood
Useful For
Detection of ethanol (ethyl alcohol) in blood to document prior consumption or administration of ethanol
Quantification of the concentration of ethanol in blood correlates directly with degree of intoxication
All testing is performed under strict chain of custody
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 always under the control of personnel involved with testing the specimen; this control implies that the opportunity for specimen tampering would be limited.
This test is not intended for use in employment-related testing.
Additional Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| COCH | Chain of Custody Processing | No | Yes |
Reporting Name
Ethanol, CoC, BSpecimen Type
Whole Blood NaFl-KOxSpecimen Required
Supplies: Chain-of-Custody Kit (T282)
Container/Tube: Chain-of-Custody Kit (T282) containing the specimen container seals and documentation required.
Preferred: Gray top (potassium oxalate/sodium fluoride)
Acceptable: Lavender (EDTA) or green top (sodium heparin)
Specimen Volume: 2 mL
Collection Instructions:
1. Do not use alcohol to clean arm. Use an alternative, such as Betadine, to cleanse arm before collecting any specimen for volatile testing.
2. Specimen must be sent in original tube. Collect specimen, seal, and submit with the associated documentation to satisfy the legal requirements for chain-of-custody testing.
Specimen Minimum Volume
0.5 mL or amount to fill 1 tube
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood NaFl-KOx | Refrigerated (preferred) | 14 days | |
| Frozen | 28 days | ||
| Ambient | 24 hours |
Reject Due To
| Gross lipemia | Reject |
| Gross icterus | OK |
Clinical Information
Ethanol is one of the most widely abused legal substances in the United States. It is the active agent in beer, wine, vodka, whiskey, rum, and other liquors.
Ethanol acts on cerebral functions 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 becomes progressively increased.
In most jurisdictions in the United States, the level of prima facie evidence of being under the influence of alcohol for purposes of driving a motor vehicle is 80 mg/dL (0.08%) in whole blood.
Chain of custody is a record of the disposition of a specimen to document the personnel who collected it, handled it, and 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.
Reference Values
Not detected (Positive results are quantified.)
Limit of detection: 10 mg/dL (0.01 g/dL)
Legal limit of intoxication is 80 mg/dL (0.08 g/dL).
Toxic concentration is dependent upon individual usage history.
Potentially lethal concentration: ≥400 mg/dL (0.4 g/dL)
Interpretation
The presence of ethanol in blood at concentrations greater than 30 mg/dL (>0.03% or g/dL) is generally accepted as a strong indicator of the use of an alcohol-containing beverage.
Blood ethanol levels above 50 mg/dL (>0.05%) are frequently associated with a state of increased euphoria.
Blood ethanol level above 80 mg/dL (>0.08%) exceeds Minnesota's legal limit for driving a motor vehicle. These levels are frequently associated with loss of manual dexterity and with sedation.
A blood alcohol level of 400 mg/dL (≥0.4%) or more may be lethal as normal respiration may be depressed below the level necessary to maintain life.
The blood ethanol level is also useful in diagnosis of alcoholism. A patient who chronically consumes ethanol will develop a tolerance to the drug and requires higher levels than described above to achieve various states of intoxication. An individual who can function in a relatively normal manner with a blood ethanol level above 150 mg/dL (>0.15%) is highly likely to have developed a tolerance to the drug achieved by high levels of chronic intake.
Cautions
Whole blood is required (not serum or plasma).
Clinical Reference
Langman LJ, Bechtel LK, Holstege CP. Clinical toxicology. In: Rifai N, Chiu RWK, Young I, Burnham CD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:454
Method Description
Specimens are analyzed and quantitated using headspace gas chromatography with flame ionization detection.(Baselt RC. Disposition of Toxic Drugs and Chemicals in Man. 10th ed. Biomedical Publications; 2014:2211)
Day(s) Performed
Monday through Saturday
Report Available
1 to 2 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80320
G0480 (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ALCX | Ethanol, CoC, B | 56478-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 36127 | Ethanol, B | 56478-1 |
| 36161 | Chain of Custody | 77202-0 |
Method Name
Headspace Gas Chromatography with Flame Ionization Detector (HSGC-FID)
Secondary ID
62709Forms
1. Chain of Custody Request is included in the Chain-of-Custody Kit (T282).
2. If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.