What cluster of blood test results would be consistent with chronic heavy alcohol use Quizlet

Indications for Testing

Laboratory testing is appropriate in the context of suspicion of alcohol use or exposure, trauma-related injury, substance abuse treatment monitoring, or follow-up testing to investigate other biomarker abnormalities that suggest alcohol use or exposure, including abnormalities in mean corpuscular volume (MCV) or in gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), or alanine aminotransferase (ALT) concentrations.

Laboratory Testing

Acute Alcohol Use Biomarkers

Ethanol

Serum ethanol testing provides the most accurate determination of a patient’s alcohol level. Acute ethanol intoxication is not reliably detected by serum ethanol testing beyond the first 6-8 hours.

Ethyl Glucuronide and Ethyl Sulfate

EtG and EtS are direct minor metabolites of ethanol and are considered good markers of acute, short-term (up to 36 hours in the blood, up to 5 days in urine) alcohol ingestion.  The sensitivity of these tests is highest in heavy drinkers but wanes after 24 hours and with lower doses.  Results do not accurately correlate with the amount or frequency of ethanol use.

Refer to the ARUP Consult Emergency Toxicology topic for more information about acute alcohol use testing.

Chronic Alcohol Use Biomarkers

Carbohydrate-Deficient Transferrin

CDT, an indirect metabolite of ethanol, is a serum marker of long-term, heavy alcohol use (≥40 g/day for up to 2 weeks) or relapse. CDT concentrations generally correlate well with an individual’s drinking pattern, especially during the preceding 30 days,  and is most useful for long-term abstinence monitoring. Factors that affect CDT levels include body mass index (BMI), female sex, and smoking.  CDT testing cannot be used in individuals suspected of having congenital glycosylation disorders.

Phosphatidylethanol

PEth is a direct ethanol metabolite and can be tested to detect longer term exposure (within 1-2 weeks or longer). Because blood PEth levels are closely correlated with alcohol consumption, PEth testing can be used to monitor alcohol consumption, identify early signs of harmful alcohol consumption, and track cases of AUD or dependence. 

Nonspecific Biomarkers

Gamma-Glutamyl Transferase

GGT is an inexpensive and sensitive indirect marker of alcohol consumption. Even moderate drinkers (<60 g/week), especially men, show higher levels of GGT than abstainers do.

The limitations of GGT include lack of specificity; levels may be elevated with nonalcoholic fatty liver disease, drug intoxication, obesity, diabetes, and hepatobiliary disorders. GGT is also age dependent; concentrations increase with age, even in abstinent individuals. Normalization of GGT requires 2-3 weeks of abstinence.

Mean Corpuscular Volume

MCV, the average size of a person’s red blood cells, increases with high quantities of alcohol ingestion.Compared with other biomarkers, MCV has low sensitivity but higher specificity for alcohol use. Because this test can detect previous alcohol exposure, even after a long period without alcohol consumption, it is not useful for monitoring abstinence in those recovering from AUD. 

Aspartate Aminotransferase and Alanine Aminotransferase

AST and ALT enzymes have low sensitivity and specificity to screen for excessive alcohol consumption, but they are highly sensitive and specific for detecting alcohol-induced liver damage.  The AST/ALT ratio increases with alcohol consumption; an AST/ALT ratio >1 is considered suggestive of alcohol as the cause of liver dysfunction.  ALT is less sensitive than AST, but both can be effective tools in combination with other biomarkers to identify heavy drinking.

Attributes of Ethanol Biomarkers

Criteria for Diagnosis

The DSM-5  includes a list of 11 criteria for defining AUD with mild, moderate, and severe subclassifications. Mild AUD is classified as the presence of two or three symptoms over the past year; moderate, four or five symptoms; and severe, six or more symptoms.  A brief description of the 11 criteria follows :

• Alcohol is often used in larger amounts or over a longer period than intended.
• The individual has had a persistent desire or unsuccessful attempts to cut down or control alcohol use.
• A significant amount of time is spent in activities necessary to obtain, use, or recover from alcohol.
• The individual has a craving or urge to use alcohol.
• Recurrent alcohol use has resulted in failure to fulfill obligations at work, school, or home.
• Alcohol use has continued despite alcohol-related social or interpersonal problems.
• Alcohol use has continued despite persistent or recurrent alcohol-related physical or psychological problems.
• Important activities have been given up or reduced because of alcohol use.
• The individual has engaged in recurrent alcohol use in physically hazardous situations.
• The individual demonstrates evidence of tolerance.
• The individual has demonstrated withdrawal symptoms or syndrome.

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