Alcohol Testing...

One of the major substances of abuse nowadays aside from cigarette smoking is ethanol (alcohol). Ethanol functions as a depressant of the central nervous system. Alcohol’s effect includes the blockage of inhibitory centers, leading to perception of being stimulated. Risk-taking behaviors often increases after the consumption of alcohol, for example, level of aggressive humor may rise. Most common cause why people tend to abuse alcohol is because of depression, economic and social problems. This is why it is considered as one the most important and controversial substance of abuse at the present time.

PHARMACOLOGY

Ethanol is consumed on different beverages which are expressed as proof. Proof is twice the percentage of ethanol in the beverage.

Example: 90 proof vodka = 45% ethanol content

Variety of alcoholic beverages contains different ethanol content as seen in the table below.

APPROXIMATE ETHANOL CONTENT OF ALCOHOLIC BEVERAGES
Beverage	Ethanol content (%)
Beer	3 – 6
Ciders	4 – 5
Wines	8 – 15
Sherry, madeira, port	18 – 20
Whiskey, gin	40 – 45
Vodka	40 – 50
Brandy	45 – 50
Rum	50 – 70

With this, we should be able to evaluate on how much ethanol has been taken in a given period of time, not on how many drinks a person has consumed. This is because ethanol will be in the bloodstream in 1 hour and there would be a specific blood alcohol level wherein intake of ethanol may be lethal. The table below will show the stages of impairment at specific blood alcohol level.

STAGES OF IMPAIRMENT BY ETHANOL
Blood Alcohol (%, w/v)	Signs and Symptoms
0.01 – 0.05	No obvious impairment, some changes observable on performance testing
0.03 – 0.12	Mild euphoria, decrease inhibitions, some impairment of motor skills
0.09 – 0.25	Decreased inhibitions, loss of critical judgment, memory impairment, diminished reaction time
0.18 – 0.30	Mental confusion, dizziness, strongly impaired motor skills (staggering, slurred speech)
0.27 – 0.40	Unable to stand or walk, vomiting, impaired consciousness
0.35 – 0.50	Coma and possible death

Blood alcohol analysis is requested whether the need is strictly medical or if some legal action may be forthcoming which would involve use of the test results. The following tests are done in the analysis of blood alcohol.

SAMPLING

1. 1.       Blood obtained from venipuncture.
2. *  Do not use with an alcohol swab when cleansing site on the arm. Instead, use soap and water.
3. 2.       8 – 10mL of whole blood in a sterile container containing oxalate and sodium fluoride.
4. 3.       Separate plasma.
5. 4.       Sample must be slightly stoppered at all times.

GAS CHROMATOGRAPHY - provides the most useful information when analyzing ethanol.

1. 1.       Serum sample is injected directly onto the column after being mixed with an internal standard.
2. 2.       Separation occurs within a few minutes.
3. 3.       Observe and identify alcohols methanol, ethanol, and isopropanol.

ENZYMATIC ANALYSIS - reaction employs alcohol dehydrogenase with NAD+ as coenzyme. Acetaldehyde  is formed as the ethanol is oxidized, with the generation of NADH used as a marker for the reaction.

COMMON INDICATORS OF ETHANOL ABUSE
GGT	Increases can be seen before the onset of pathologic consequences.
AST	Increases in serum activity can occur in many non-ethanol-related conditions.
AST/ALT ratio	A ratio greater than 2.0 is highly specific for ethanol-related liver disease.
HDL	High serum HDL is specific for ethanol consumption.
MCV	Increased erythrocyte MCV is commonly seen with excessive ethanol consumption.
	Increases are not related to folate or vitamin B12 deficiency.