Alkaline Phosphatase and Isoenzymes Core Lab Study
Synonym/Acronym
Alk Phos, ALP and fractionation, heat-stable ALP.
Rationale
Alkaline phosphatase (ALP) is used to assist in the diagnosis of liver and bone disease.
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.
ALP 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, 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 for total alkaline phosphatase, inhibition/electrophoresis for fractionation.
| Age/Gender | Total ALP Conventional and SI Units | Bone Fraction Conventional and SI Units | Liver Fraction Conventional and SI Units |
|---|
| Newborn | | | | | Male | 75–375 units/L | NA | NA | | Female | 65–350 units/L | NA | NA | | 1–8 yr | | | | | Male | 70–364 units/L | 50–319 units/L | Less than 8–76 units/L | | Female | 73–378 units/L | 56–300 units/L | Less than 8–53 units/L | | 9–12 yr | | | | | Male | 112–476 units/L | 78–339 units/L | Less than 8–81 units/L | | Female | 98–448 units/L | 78–353 units/L | Less than 8–62 units/L | | 13–14 yr | | | | | Male | 112–476 units/L | 78–389 units/L | Less than 8–48 units/L | | Female | 56–350 units/L | 28–252 units/L | Less than 8–50 units/L | | 15 yr | | | | | Male | 70–378 units/L | 48–311 units/L | Less than 8–39 units/L | | Female | 42–168 units/L | 20–115 units/L | Less than 8–53 units/L | | 16 yr | | | | | Male | 70–378 units/L | 48–311 units/L | Less than 8–39 units/L | | Female | 28–126 units/L | 14–87 units/L | Less than 8–50 units/L | | 17 yr | | | | | Male | 56–238 units/L | 34–190 units/L | Less than 8–39 units/L | | Female | 28–126 units/L | 17–84 units/L | Less than 8–53 units/L | | Adult | | | | | Male | 35–142 units/L | 11–73 units/L | 0–93 units/L | | Female | 25–125 units/L | 11–73 units/L | 0–93 units/L |
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Study type: Blood collected in a gold-, red-, red/gray-, or green-top [heparin] tube; related body system: Digestive and Musculoskeletal systems.
ALP is an enzyme found in the liver; in Kupffer cells lining the biliary tract; and in bones, intestines, and placenta. Other sources of ALP include the proximal tubules of the kidneys, pulmonary alveolar cells, germ cells, vascular bed, lactating mammary glands, and granulocytes of circulating blood. ALP is referred to as alkaline because it functions optimally at a pH of 9.
There are a number of isoenzymes of ALP. Elevations in two main ALP isoenzymes, however, are of clinical significance and are used to identify the source of increased ALP levels: ALP1 of liver origin and ALP2 of bone origin. Measurement of bone-specific ALP is also used as an indicator of increased bone turnover and estrogen deficiency in postmenopausal women.
ALP is most often used in combination with other liver enzymes to assist in the diagnosis of liver disease. Together, increases in levels of ALP and the liver enzyme gamma-glutamyl transpeptidase (GGT) help differentiate cholestasis from other liver diseases. Isolated increases in ALP levels are usually related to non-hepatic conditions such as pregnancy or diseases of the bone, kidneys (chronic), lymph nodes.
| Examples of Possible Patterns Between ALP Levels and Other Core LFT Levels in Specific Hepatic Conditions |
|---|
| Diagnosis | ALP Level (Other Core LFTs) |
|---|
| Cholestasis | Marked ↑↑↑ (Alb ↓, ALT ↑, AST ↑, TBil ↑) Marked elevations of ALP and GGT are indicative of cholestasis. | | Cirrhosis | Normal to Mild or Moderate ↑to↑↑ (Alb ↓, ALT ↑ to ↑↑, AST ↑↑↑, TBil ↑) | | Hepatitis, viral, acute | Normal to Mild or Moderate ↑ to ↑↑ (Alb ↓, ALT ↑↑↑, AST ↑↑↑, TBil ↑ to ↑↑) | | Hepatitis, toxin or drug related | Normal to Mild or Moderate ↑ to ↑↑ (Alb ↓, ALT ↑↑↑, AST ↑↑↑, TBil ↑↑) | | Infarction, acute necrosis of the liver, or cancer | Normal to Mild or Moderate ↑ to ↑↑ (Alb ↓, ALT ↑↑↑, AST ↑↑ to ↑↑↑, TBil ↑↑) | | Jaundice, hepatic origin | Normal to Mild or Moderate ↑ to ↑↑ in obstructive hepatic jaundice (Alb ↓, ALT ↑↑ with ALT rising before AST and TBil, AST ↑↑, TBil ↑ to ↑↑) |
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. |
Factors That May Alter the Results of the Study
- Drugs and other substances that may increase ALP levels by causing cholestasis related to diseases of the liver, bile duct, or pancreas that result in impaired flow of bile include anabolic steroids, erythromycin, ethionamide, gold salts, imipramine, interleukin-2, isocarboxazid, nitrofurans, oral contraceptives, phenothiazides, sulfonamides, and tolbutamide.
- Drugs and other substances that may increase ALP levels include acarbose, ACE inhibitors, acetaminophen (toxic), acetylsalicylic acid, allopurinol, amoxicillin, amiodarone, ampicillin, amytriptyline, ARBs, 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 related to release of ALP from hemplyzed RBCs.
- Elevations of ALP may occur if the patient is nonfasting, usually 2 to 4 hr after a fatty meal related to increases in intestinal ALP levels.
- Young children may have increased ALP levels during growth spurts.
Increased In
Related to release of alkaline phosphatase from damaged bone, biliary tract, and liver cells.
- Liver disease:
- Biliary atresia
- Biliary obstruction (especially cholestasis), intra- or extra- (acute cholecystitis, cholelithiasis, intrahepatic cholestasis of pregnancy, primary biliary cholangitis)
- Cancer
- Cirrhosis
- Diabetes (diabetic hepatic lipidosis)
- Granulomatous or infiltrative liver diseases (sarcoidosis, amyloidosis, tuberculosis)
- Hepatitis
- Infectious mononucleosis
- Bone disease:
- Other conditions:
- Advanced pregnancy (related to additional sources: placental tissue and new fetal bone growth; marked decline is seen with placental insufficiency and imminent fetal demise)
- Cancer of the breast, colon, gallbladder, lung, or pancreas
- Familial hyperphosphatemia
- Heart failure
- HELLP syndrome of pregnancy (hemolysis, elevated liver enzymes, low platelet count)
- Hyperparathyroidism
- Perforated bowel
- Pneumonia
- Pulmonary and myocardial infarctions
- Pulmonary embolism
- Ulcerative colitis
Decreased In
Potential Nursing Problems: Assessment & Nursing Diagnosis
| Problems | Signs and Symptoms |
|---|
| Confusion (related to neurosensory changes associated with increased cerebral ammonia levels related to substance use disorder [alcohol], chronic viral hepatitis [B,C], hepatic encephalophy, hepatic metabolic insufficiency, biliary cirrhosis, hereditary hemochromatosis, non-alcoholic fatty liver disease, autoimmune hepatitis) | 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 (excess fluid volume related to increased protal venous pressure, imbalanced aldosterone; hypoalbuminemia; inadequate protein intake, low serum oncotic pressure) | Weight gain; increasing abdominal girth; abdomen is taut and dull to percussion; jugular vein distention; altered breathing patterns, shortness of breath, crackles; increasing central venous pressure; dehydration; edema | | 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 | | Nutrition(insufficient nutrition related to the inability to ingest or digest food, psychological factors [anorexia, bulimia], inability to absorb nutrients, inadequate dietary intake, inadequate financial resources) | Weight loss regardless of sufficient intake, ideal body weight is greater than 20% less of ideal weight, intake is less then the recommended dietary allowance, excessive hair loss, weakness, lack of interest in food or eating, pale mucous membranes, mouth sores, fatigue, listlessness | | 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 |
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Before the Study: Planning and Implementation
Teaching the Patient What to Expect
- Discuss how this test can assist with determining the presence of liver or bone 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 observed for development of ascites, which requires strict attention to fluid and electrolyte balance.
Treatment Considerations
- Monitor and trend vital signs.
- Monitor and trend laboratory studies associated with hydration (BUN and Cr) and potassium loss due to nasogastric suction.
- Monitor and trend ALP.
- Compare ALP with GGT, LFTs (Alb, ALT, AST, TBil, DBil, TP) or other related studies to track the course of disease and response to treatment.
- Note that PT will be prolonged and INR increased if liver function is significantly damaged.
Confusion
- Observe for altered attention span, inability to give an accurate history, loss of concentration, inability to follow commands, behavior that is inappropriate or violent, inappropriate affect.
- Institute fall precautions, assist with activity, lower bed position, use restraints as necessary.
- Try reorientation to person, place, time, and purpose.
- Administer prescribed medications; lactalose, nonhepatic metabolized sedatives.
- Encourage family to assist in providing an emotionally stable environment.
Fluid Volume
- Facilitate management of fluid volume excess.
- Assess for ascites in the peritoneal cavity as excess fluid may impinge on both respiratory and digestive function.
- Measure abdominal girth at the same place each day.
- Access for abdominal dullness with percussion.
- Monitor both fluid intake and urinary output.
- Enforce ordered fluid limit.
- Administer prescribed diuretics (spironolactone); facilitate paracentesis as needed; abdominal binder; facilitate use of incentive spirometer.
- Assess for signs of portal hypertension and gastrointestinal bleed.
- Collaborate with the HCP and pharmacist for fluid and electrolyte management if NPO status is required.
Gas Exchange, Risk
- Facilitate management of gas exchange alterations.
- Monitor pulse oximetry, administer oxygen as ordered.
- Position in high Fowlers to maximize lung expansion.
- Obtain baseline abdominal girth, measure and mark each shift or as needed to monitor growth.
- Consider use of incentive spirometry.
- Encourage deep breathing and repositioning.
Nutrition
- Facilitate management of insufficient nutrition.
- Obtain daily weight, calorie count; consider counseling, dietary consult.
- Assess current eating patterns and attitudes toward food.
- Monitor and trend laboratory values associated with nutrition, serum albumin, transferrin, RBC count, WBC count, electrolytes.
- Facilitate a pleasant eating environment; consider championship during meals to enhance appetite.
- Provide culturally appropriate foods from home.
- Discourage caffeinated or carbonated drinks as they may sate the appetite.
- Administer ordered nutrition supplements.
- Facilitate speech therapy consult if impaired swallowing is noted.
- Administer ordered parenteral fluids with strict intake and output and daily weight.
- Administer ordered NSAIDs, opioids, and antiemetics to facilitate improved nutrition management.
- Discourage alcohol use as it can interfere with adequate nutrition related to insufficient dietary intake.
Skin, Risk
- Assess skin general condition noting any scratches, bruises, excoriation, rash.
- Monitor bilirubin level as a level greater than 3 mg/dL facilitates jaundice and increases itching risk.
- Discuss ways to protect the skin such as use of tepid water, alkaline soap, and emollient lotions.
- Suggest keeping short fingernails and the use of mittens to discourage scratching.
- Loose-fitting cotton clothing, cool room temperatures, and administration of antihistamines can help decrease itching.
Safety Considerations
- Consider fall precaution interventions that can limit injury risk to those with progressive compromised bone stability or liver function, and confusion.
Nutritional Considerations
- Note that increased ALP levels may be associated with liver disease.
- Patients in general should be encouraged to eat a well-balanced diet that includes foods high in fiber.
- Recognize that dietary recommendations will vary depending on the patient’s condition and disease severity (e.g., a soft foods diet is recommended if esophageal varices develop, fat substitutes are recommended if bile duct disease is diagnosed, or salt intake should be limited if ascites develop).
- Consider a dietary consult with discussion of culturally appropriate foods.
Clinical Judgement
- Consider how altered liver function can impinge upon an individual’s ability to meet life goals by interfering with personal health and choose implementation strategies that will facilitate positive health choices.
Follow-Up and Desired Outcomes
- Agrees to make lifestyle changes that will improve overall health.
- Understands that small, frequent meals throughout the day can increase overall caloric intake and improve nutritional status.
- Demonstrates awareness that cessation of weight loss with some weight gain may occur over a specified period of time.