Ethanol/Volatiles Screen (EVS)
| Order Code: | EVS |
| Order Form: | Laboratory Requisition |
Specimen:
Plasma
Collection Medium:
 |
| Plasma Separator Tube |
Alternate
Collection Media:
Call laboratory for additional acceptable specimen collection containers.
Minimum:
3 mL whole blood from light green top tube or TWO microtainers
Rejection Criteria:
Medico-legal specimens are not accepted.
Testing
Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around
Time:
1 hour (upon receipt in laboratory)
Reference Range:
None detected. Ethanol intoxication begins in the 50-100 mg/dL range.
Critical value: >300 mg/dL
Comments:
An EVS includes plasma ethanol, plasma osmolality, and a calculated
osmolality using plasma sodium, glucose and urea. See links below for
further information concerning the osmolality gap. Samples with
unexplained osmolar gap greater than 15 have "Ethylene glycol" (by
enzymatic assay) run reflexively. For those samples, if the ethylene
glycol plasma concentration does not account for the high osmolar gap,
the pathology resident on-call is contacted.
An osmolality gap of > 15 will be called to the requesting facility by Pathology staff to discuss findings and determine if gas chromatography testing is warranted. A preliminary Ethanol/Volatiles Screen (EVS) will be performed on all sample requests for alcohol or glycols (ethylene or propylene) testing by gas chromatography.
Elevated osmolar gaps may be caused by methanol, isopropanol, propylene glycol, activated charcoal, mannitol, renal failure, and diabetic ketoacidosis, as well as by heavy ethanol consumption with high concentrations of ethanol metabolites (in some cases with little or no ethanol remaining) as may be seen in alcoholic ketoacidosis.
Availability: as needed.
An osmolality gap of > 15 will be called to the requesting facility by Pathology staff to discuss findings and determine if gas chromatography testing is warranted. A preliminary Ethanol/Volatiles Screen (EVS) will be performed on all sample requests for alcohol or glycols (ethylene or propylene) testing by gas chromatography.
Elevated osmolar gaps may be caused by methanol, isopropanol, propylene glycol, activated charcoal, mannitol, renal failure, and diabetic ketoacidosis, as well as by heavy ethanol consumption with high concentrations of ethanol metabolites (in some cases with little or no ethanol remaining) as may be seen in alcoholic ketoacidosis.
Availability: as needed.
Test
Limitations:
Icterus: No significant interference from bilirubin up to an I index of
60.
Lipemia: No significant interference from lipemia up to an L index of
500.
Hemolysis: >1,000 mg/dL will be canceled.
References:
(1) Young DS. Effects of Drugs on Clinical Laboratory Tests. 3rd ed.
Washington, DC: AACC Press; 1990.
(2) Young DS. Effects of Preanalytical Variables on Clinical Laboratory
Tests. Washington, DC: AACC Press; 1993: 3-120, 3-121.
Methodology:
Enzymatic (ethanol); freezing point depression osmometry (osmolality);
calculation (osmolality, calculated)
Instructions:
Separate plasma from cells ASAP.
Sample
Processing:
Centrifuge at 3000 RPM for 10 minutes.
Label transport tube with two patient identifiers, date and time of collection.
Label transport tube with two patient identifiers, date and time of collection.
Sample
Storage:
Refrigerate.
Transport
Instructions:
Place requisition into outside pocket of bag.
Place specimen into zip-lock type bag, seal bag.
Transport in cooler with refrigerated coolant packs.
Place specimen into zip-lock type bag, seal bag.
Transport in cooler with refrigerated coolant packs.
CPT Code:
82055
See Additional Information:
Chemistry Critical Lab Values
Osmolality Gap - Calculation and Interpretation
Osmolality Gap Calculator
Chemistry Critical Lab Values
Osmolality Gap - Calculation and Interpretation
Osmolality Gap Calculator