Alanine Aminotransferase

General

Core Lab Study

Synonym/Acronym:
aminotransferase, ALT.

Rationale
To assess liver function related to liver disease and/or damage; differentiate between jaundice related to liver disease and jaundice related to red blood cell (RBC) hemolysis.

This Core Lab Study is included in the liver function test (LFT) panel 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, and malnutrition.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.

Normal Findings
Method: Spectrophotometry.

AgeConventional and SI Units
Newborn7–41 units/L
Child, adult
Male19–36 units/L
Female24–36 units/L
Greater than 90 yr
Male6–38 units/L
Female5–24 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

Overview

(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 nonhepatic jaundice
Jaundice, RBC originALT ↑ 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.

Indications

  • Differentiate jaundice related to liver disease vs jaundice related to RBC hemolysis.
  • Monitor liver damage resulting from liver disease and infections.
  • Monitor liver damage resulting from hepatotoxic chemicals and drugs.
  • Monitor response to treatment of liver disease, with tissue repair indicated by gradually declining levels.

Interfering Factors

  • Drugs and other substances that may increase ALT levels include acarbose, angiotensin-converting enzyme inhibitors, acetaminophen (toxic), acetylsalicylic acid, allopurinol, amoxicillin, amiodarone, ampicillin, amytriptyline, angiotensin II receptor blockers, asparaginase, azathioprine, beta blockers, baclofen, bupropion, carbamazepine, cephalosporins, chloramphenicol, chlordiazepoxide, chlorpromazine, chlorpropamide, clindamycin, cloxacillin, clopidogrel, codeine, cyproheptadine, cytarabine, danazol, desipramine, dicumarol, doxepin, enflurane, erythromycin, estrogens, ethambutol, ethionamide, ethotoin, ethyl alcohol, fibrates, gentamicin, gold salts, imipramine, isoniazid, ketoconazole, low-molecular-weight heparin, methyl dopa, metaxalone, methotrexate, nafcillin, naladixic acid, nitrofurans, nortriptyline, NSAIDs, omeprazole, oral contraceptives, oxacillin, phenobarbital, phenytoin, probenecid, procainamide, propoxyphene, pyrazinamide, quinidine, rifampin, risperidone, sulfonamides, terbinafine, tetracyclines, trazadone, trimethoprim, valproic acid, verapamil, and zidovudine.
  • Hemolyzed specimens may cause falsely elevated results.

Potential Medical Diagnosis: Clinical Significance of Results

Increased in

Related to release of ALT from damaged liver, kidney, heart, pancreas, RBCs, or skeletal muscle cells.

  • AIDS (related to hepatitis B coinfection)
  • Acute autoimmune hepatitis
  • Biliary tract obstruction (passage of stone from common bile duct can produce moderate, transient increase)
  • Budd-Chiari syndrome (acute)
  • Burns (severe)
  • Cirrhosis
  • Fatty liver (e.g., acute fatty liver of pregnancy)
  • HELLP syndrome of pregnancy; variant of pre-eclampsia (hemolysis, elevated liver enzymes, low platelet count)
  • Hepatic cancer
  • Hepatic infarction or necrosis
  • Hepatitis (drug or toxin induced)
  • Hepatitis, viral (acute or reactivation)
  • Infectious mononucleosis
  • Muscle injury from intramuscular injections, trauma, infection, and seizures (recent)
  • Muscular dystrophy
  • Myositis
  • Nonalcoholic fatty liver disease
  • Pancreatitis (acute)
  • Pre-eclampsia
  • Shock (severe)
  • Substance use disorder (alcohol)
  • Wilson disease (acute)

Decreased in

  • Pyridoxal phosphate deficiency (related to a deficiency of pyridoxal phosphate that results in decreased production of ALT)

Nursing Implications, Nursing Process, Clinical Judgement

Potential Problems: Assessment & Nursing Diagnosis/Analysis

ProblemsSigns and Symptoms
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 hypoalbuminemia, 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.

Before the Study: Planning and Implementation


Teaching the Patient What to Expect

  • Discuss how this test can assist with evaluation of liver function and help identify liver disease.
  • Explain that a blood sample is needed for the test.

After the Study: Implementation & Evaluation Potential Nursing Actions


Avoiding Complications

  • The patient with cirrhosis should be carefully observed for the development of ascites, in which case fluid and electrolyte balance requires strict attention.
  • Interventions/actions related to skin risk include the following: Assess general skin condition noting any scratches, bruises, excoriation, or rash. Consider ways to protect the skin, such as use of tepid water, alkaline soap, and emollient lotions. Decrease itching with the use of loose-fitting cotton clothing, cool room temperatures, and administration of antihistamines. Keep fingernails short and suggest the use of mittens to discourage scratching.

Treatment Considerations

  • Monitor and trend labs: ALT. ALT levels may be lower than expected in liver disease attributable to substance use disorder (alcohol) related to a dietary deficiency of pyridoxyl-5–phosphate, an essential cofactor for ALT synthesis. Compare with LFTs (Alb, ALP, AST, TBil, DBil, TP) or other related studies to track the course of disease and response to treatment. Monitor blood alcohol and ammonia levels. If liver function is significantly damaged, PT will be prolonged and INR increased. Trend PT, INR, H&H, and ABG results.

Fluid Volume, Deficit

  • Facilitate management of fluid volume deficit.
  • Collaborate with health-care provider (HCP) regarding administration of IV fluids to support optimal hydration.
  • Interventions/actions related to fluid volume deficit include the following: Monitor laboratory values that reflect alterations in fluid status: K+, BUN, Ca, Cr, Hgb, and Hct. Administer ordered replacement electrolytes. Manage underlying cause of fluid alteration, and monitor urine characteristics (color, dark), respiratory status; trend vital signs. Perform a daily weight with strict intake and output.

Fluid Volume, Excess

  • Facilitate management of fluid volume excess.
  • Interventions/actions related to fluid volume excess include the following: Monitor for abdominal ascites; measure and trend abdominal girth. Assess for dependent edema in hands and feet, the neck for jugular venous distention, and the lungs for crackles. Evaluate for shortness of breath. Administer ordered oxygen, and trend oxygenation with pulse oximetry. Monitor and trend laboratory values: Alb, TP, and globulin. Administer ordered diuretics; monitor urinary output in response to therapeutic interventions; trend vital signs and daily weight, and perform strict intake and output. Use high Fowler position to maximize lung expansion improving gas exchange; also, encourage deep breathing and repositioning, and consider use of incentive spirometry.

Safety Considerations

  • Interventions/actions related to fall risk include the following: Institute fall precautions. Assist with activity. Maintain low bed position. Use restraints as necessary (judicious and appropriate).
  • Interventions/actions related to confusion include the following: Reorient to person, place, time, and purpose; encourage family to assist in providing an emotionally stable environment. Observe for altered attention span, inability to give an accurate history, loss of concentration, inability to follow commands, behavior that is inappropriate or violent, or inappropriate affect.
  • Monitor and trend vital signs for alterations associated with metabolic imbalances.
  • For bleeding concerns, monitor for bleeding, administer ordered blood and blood products per facility protocol.

Nutritional Considerations

  • Dietary recommendations will vary depending on disease condition and severity; e.g., a soft food diet is recommended if esophageal varices develop; fat substitutes are recommended if bile duct disease is diagnosed; limited salt intake is recommended if ascites develop; frequent small meals high in calories from carbohydrates or high-fiber diet may be required as indicated. Discuss how a diet low in protein and other foods such as onions, gelatin, or string beans can decrease ammonia levels and may improve cognitive function.
  • Interventions/actions related to nutrition include the following: Monitor and trend laboratory values that evaluate nutritional status (Alb, TP, K+); collaborate with HCP and pharmacist on replacement strategies. Record intake and output. Record daily weight. Evaluate nutritional history that includes cultural food preferences. Facilitate dietary intake; administer ordered enteral or parenteral nutrition. Manage pain as it adversely affects appetite; consider administration of antiemetics and acid suppression agents.

Clinical Judgement

  • Consider why personal choices have resulted in poor health outcomes and which interventions are most likely to result in adaptation to a more healthy lifestyle and improved health.

Followup Evaluation and Desired Outcomes

  • Acknowledges contact information provided for the Centers for Disease Control and Prevention (www.cdc.gov/diseasesconditions).
  • Understands information regarding causative factors of pancreatitis and liver disease, the disease process, and proactive lifestyle changes to better manage health.
  • Accepts the importance of adhering to the medication regimen as prescribed to limit pancreatic secretions and decrease pain.