Laboratory Tests and Ancillaries
Lab and Diagnostic
Tests
Liver function tests
(LFTs) may reveal a total bilirubin >3 mg/dL and albumin <3 g/L, as well
as prolonged prothrombin time (PT), which may be used in determining the
prognosis of patients with alcohol-related hepatitis. Elevation of aspartate
aminotransferase (AST) and alanine aminotransferase (ALT) may occur, with
AST>ALT, usually >2x the upper limit of normal. An AST:ALT ratio >1.5
gives a likely diagnosis of ALD; if the ratio is ≥3, this is strongly
suggestive of ALD. Alkaline phosphatase and gamma-glutamyl transpeptidase (GGT)
(>100 U/mL) are both usually elevated, with the latter being a marker for
detection of previous alcohol consumption.
A complete blood
count is used to evaluate for hematological abnormalities. Macrocytic anemia
may be seen in 75% of patients, while thrombocytopenia may be transitory only.
However, if there is progression to cirrhosis, it may persist. Leukocytosis,
including a leukemoid reaction in the absence of infection, may also occur.
Metabolic and
biochemical tests include blood glucose, lipid profile, serum uric acid, and
serum electrolytes. Metabolic alterations such as hyperglycemia,
hypertriglyceridemia, hyperuricemia, and electrolyte abnormalities may be
present.
Alcohol biomarkers (eg
urine ethyl sulfate, urine and hair ethyl glucuronide, and phosphatidylethanol [Peth])
may be considered, where available, to support the assessment of recent or
ongoing alcohol use. These are direct markers for alcohol consumption that aid
in the diagnosis and support recovery. They may also be used to identify recent
alcohol use in patients who cannot be interviewed due to intoxication or
encephalopathy, or when reported alcohol use is suspected to be inaccurate. Additionally,
measurement of urine or hair ethyl glucuronide can accurately monitor
abstinence.
Assessment of
hepatic dysfunction or severity may utilize Child-Pugh classification, which is
a scoring system that uses albumin level, PT, international normalized ratio
(INR), bilirubin level, presence of ascites, and encephalopathy severity.
Assessment of liver fibrosis may use non-invasive tests (NITs), which are based
on standard blood tests, and include Fibrosis-4 (FIB-4), AST to platelet ratio
index (APRI), and enhanced liver fibrosis (ELF) test. Liver fibrosis assessment
is considered in those who consume >14 units/week with cofactors for liver
disease, such as obesity, and a specialist referral should be made for those
identified as being at high risk of advanced fibrosis or cirrhosis after NIT
assessment. Annual liver fibrosis re-assessment may be done in those who are at
low risk for advanced fibrosis but continue to consume alcohol beyond the
recommended limits.
Liver Biopsy
It must be noted
that that liver biopsy is rarely needed to establish the diagnosis of ALD.
However, it may be used to clarify atypical cases or uncertain diagnosis,
determine if any concomitant disease is present, establish stage and severity
of the disease and define the prognosis, and to aid in therapeutic decision
making.
Infectious Disease
Work-up
Risk of infection is
increased with alcohol consumption and infection commonly causes decompensated
liver disease, thus infectious screening should be done in patients with
decompensated ALD or alcohol-related hepatitis.
Imaging
Imaging studies like
ultrasound, computed tomography (CT) scan, or magnetic resonance imaging (MRI)
cannot document alcohol as the etiology of the liver disease but can help in
ruling out other causes of abnormal test results such as biliary obstruction, infiltrative
and neoplastic liver diseases. Transient elastography measures liver stiffness
in the evaluation of liver fibrosis of ALD. Ultrasound examination with or without alpha-fetoprotein measurement
every 6 months may be performed to screen for hepatocellular carcinoma in
patients with ALD cirrhosis.
Alcohol-Related Liver Disease_Diagnostics