Core Lab Study
Synonym/Acronym:
ALT.
Rationale
To assess liver function related to liver disease and/or damage; differentiate between jaundice related to liver disease and jaundice related to RBC hemolysis.
A small group of studies in this manual have been identified as Core Lab Studies. The designation is meant to assist the reader in sorting the basic “always need to know” laboratory studies from the hundreds of other valuable studies found in the manual—a way to begin putting it all together.
Normal, abnormal, or various combinations of core lab study results can indicate that all is well, reveal a problem that requires further investigation with additional testing, signal a positive response to treatment, or suggest that the health status is as expected for the associated situation and time frame.
ALT is included in the liver function test panel (LFTs) and in the comprehensive metabolic panel (CMP). LFTs are used to identify liver disease, assess severity of injury, or monitor disease process and response to treatment. CMPs are used as a general health screen to identify or monitor conditions such as bone disease, diabetes, electrolyte imbalance, hypertension, kidney disease, liver disease, or malnutrition.Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.
Normal Findings
Method: Spectrophotometry.
Age | Conventional and SI Units | ||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Newborn | 7–41 units/L | ||||||||||||||||||||||||||||||||||||||||
Child, Adult | |||||||||||||||||||||||||||||||||||||||||
Male | 19–36 units/L | ||||||||||||||||||||||||||||||||||||||||
Female | 24–36 units/L | ||||||||||||||||||||||||||||||||||||||||
Greater than 90 yr | |||||||||||||||||||||||||||||||||||||||||
Male | 6–38 units/L | ||||||||||||||||||||||||||||||||||||||||
Female | 5–24 units/L | ||||||||||||||||||||||||||||||||||||||||
Values may be slightly elevated in older adults due to the effects of medications and the presence of multiple chronic or acute diseases with or without muted symptoms. |
Critical Findings and Potential Interventions
N/A
(Study type: Blood collected in a gold-, red-, red/gray-, or green-top [heparin] tube; related body system: Digestive system.)
ALT is an enzyme produced by the liver. The aminotransferases (ALT and AST) are indicators of liver injury, evidenced by increased serum levels related to enzymes leaking from damaged cells into the circulating blood. The highest concentration of ALT is found in liver cells (hepatocytes); smaller amounts are found in the heart, kidneys, pancreas, spleen, skeletal muscle, and RBCs. ALT is a sensitive and more specific indicator of liver disease than AST.
Examples of Possible Patterns Between ALT Levels and Other Core LFT Levels in Specific Hepatic Conditions | |||||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Diagnosis | ALT Level (Other Core LFTs) | ||||||||||||||||||||||||||||||||||||||||
Cholestasis | ↑ Normal to Mild (Alb ↓, ALP ↑↑↑, AST ↑, TBil ↑) | ||||||||||||||||||||||||||||||||||||||||
Cirrhosis | ↑ to ↑↑ Normal to Mild or Moderate (Alb ↓, ALP ↑ to ↑↑, AST ↑↑↑, TBil ↑) | ||||||||||||||||||||||||||||||||||||||||
Hepatitis, viral, acute | ↑↑↑ Marked (Alb ↓, ALP ↑ to ↑↑, AST ↑↑↑, TBil ↑ to ↑↑) | ||||||||||||||||||||||||||||||||||||||||
Hepatitis, toxin or drug related | ↑↑↑ Marked (Alb ↓, ALP ↑ to ↑↑, AST ↑↑↑, TBil ↑↑) | ||||||||||||||||||||||||||||||||||||||||
Infarction, acute necrosis of the liver, or cancer | ↑↑↑ Marked (Alb ↓, ALP ↑ to ↑↑, AST ↑↑ to ↑↑↑, TBil ↑↑) | ||||||||||||||||||||||||||||||||||||||||
Jaundice, hepatic origin | ↑↑ Mild to Moderate with ALT rising before AST and TBil (Alb ↓, ALP ↑ to ↑↑, AST ↑↑, TBil ↑ to ↑↑) | ||||||||||||||||||||||||||||||||||||||||
Relative ALT and TBil levels in non-hepatic jaundice | |||||||||||||||||||||||||||||||||||||||||
Jaundice, RBC origin | ALT ↑ Normal to Mild and TBil ↑↑ Mild to Moderate or ↑↑↑ Marked, in proportion to the degree of hemolysis | ||||||||||||||||||||||||||||||||||||||||
N = Normal, ↓ Normal to Mild decrease, ↑ Normal to Mild increase, ↑ to ↑↑ Normal to Mild or Moderate, ↑↑ Mild to Moderate, ↑↑↑ Marked. Study levels will vary with degree and progression of liver damage. ALT levels remain elevated longer than AST levels. |
Factors that may alter the results of the study
Related to release of ALT from damaged liver, kidney, heart, pancreas, red blood cells, or skeletal muscle cells.
Problems | Signs and Symptoms |
---|---|
Bleeding, risk (related to altered clotting factors, portal hypertension) | Cool extremities, delayed capillary refill, decreased distal pulses, altered mental status, hypotension, tachycardia, decreased level of consciousness. Bruises easily, hematemesis, weakness, shortness of breath, bloody or black stools. PT prolonged greater than 13.5 seconds. |
Confusion, risk (related to neurosensory changes associated with cerebral ammonia accumulation related to substance use disorder [alcohol], hepatic metabolic insufficiency, hepatic encephalopathy) | Disoriented to person, place, time, and purpose; inability to follow directions or provide an adequate history; delusions; inappropriate behavior; violence that is directed to self or others; inappropriate affect; forgetfulness, anxiety, fearfulness, short attention span; personality changes; mood swings; difficulty or inability to perform mental tasks such as simple math; changed sleep patterns such as confusing day and night to extreme sleepiness; difficult slow or sluggish hand movement, jumbled slurred speech, or inability to perform familiar purposeful actions |
Fluid volume (deficit—related to vomiting, decreased intake, compromised kidney function, overly aggressive diuresis) | Decreased urinary output, fatigue, sunken eyes, dark urine, decreased blood pressure, increased heart rate, altered mental status, dehydration, poor skin turgor |
Fluid volume (excess—overload related to overly aggressive fluid resuscitation; ascites related to hypoalbumenia, imbalanced aldosterone, altered [low] serum osmotic pressure) | Fluid resuscitation: edema, shortness of breath, rales, rhonchi, and diluted laboratory values. Abdominal ascites-increasing abdominal girth. Fluid resuscitation and abdominal ascites: increased weight. |
Gas exchange, risk (ineffective—related to blood loss secondary to ineffective clotting factors, increased abdominal girth secondary to liver cirrhosis) | Orthopnea, dyspnea, shortness of breath at rest or with activity, pallor, shallow respirations, cyanosis, altered blood gas, increasing abdominal girth |
Gastrointestinal (related to altered motility, irritation of the GI tract, taste alterations, pancreatic and gastric secretions) | Nausea, vomiting, abdominal distention, unexplained weight loss, steatorrhea, diarrhea, visible abdominal distention, ascites, diminished or absent bowel sounds |
Nutrition (insufficient—related to metabolic imbalances, excess alcohol use, nausea, malabsorption, anorexia) | Increased liver function tests; hyperglycemia with polyuria, weight loss, weakness, nausea, vomiting; hypocalcemia with confusion, intestinal cramping, diarrhea; hypertriglyceridemia; altered thiamine with weakness, confusion |
Pain (related to organ inflammation and surrounding tissues, excessive alcohol intake, infection) | Emotional symptoms of distress, crying, agitation, facial grimace, moaning, verbalization of pain, rocking motions, irritability, disturbed sleep, diaphoresis, altered blood pressure and heart rate, nausea, vomiting, self-report of pain, upper abdominal and gastric pain after eating fatty foods or alcohol intake with acute pancreatic disease, pain may be decreased or absent in chronic pancreatic disease |
Skin, risk (related to elevated serum bilirubin levels and excess bile salt resulting in tissue irritation and histamine release, jaundice associated with liver disease) | Reports itchy skin (dermatitis/pruritis); chronic scratching; dry, scaly skin; yellow skin and sclera; visible scratch marks with or without scabbing; rash |
Teaching the Patient What to Expect
Avoiding Complications
Treatment Considerations
Bleeding, Risk
Confusion, Risk
Fluid Volume, Deficit
Fluid Volume, Excess
Gas Exchange, Risk
Gastrointestinal
Nutrition
Pain
Skin, Risk
Nutritional Considerations
Clinical Judgement
Followup Evaluation and Desired Outcomes