Test Catalog

Test Id : ALKI

Alkaline Phosphatase, Total and Isoenzymes, Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Diagnosis and treatment of liver, bone, intestinal, and parathyroid diseases


Determining the tissue source of increased alkaline phosphatase (ALP) activity in serum


Differentiating between liver and bone sources of elevated ALP

Profile Information
A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.

Test Id Reporting Name Available Separately Always Performed
ALP Alkaline Phosphatase, S Yes Yes
ALKE Alkaline Phosphatase Isoenzymes, S No Yes

Method Name
A short description of the method used to perform the test

ALP: Colorimetric

ALKE: Electrophoresis

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Alkaline Phosphatase, Tot and Iso,S

Specimen Type
Describes the specimen type validated for testing


Necessary Information

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL, divided

Collection Instructions: Centrifuge and aliquot serum into 2 tubes, each containing 0.5 mL

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

0.5 mL divided into 2 tubes each containing 0.25 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 14 days
Ambient 7 days
Refrigerated 7 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Diagnosis and treatment of liver, bone, intestinal, and parathyroid diseases


Determining the tissue source of increased alkaline phosphatase (ALP) activity in serum


Differentiating between liver and bone sources of elevated ALP

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Alkaline phosphatase (ALP) is present in a number of tissues including liver, bone, intestine, and placenta. The activity of ALP found in serum is a composite of isoenzymes from those sites and, in some circumstances, placental or Regan isoenzymes. Serum ALP is of interest in the diagnosis of 2 main groups of conditions: hepatobiliary disease and bone disease associated with increased osteoblastic activity.


A rise in ALP activity occurs with all forms of cholestasis, particularly with obstructive jaundice. The response of the liver to any form of biliary tree obstruction is to synthesize more ALP. The main site of new enzyme synthesis is the hepatocytes adjacent to the biliary canaliculi.


ALP is also elevated in disorders of the skeletal system that involve osteoblast hyperactivity and bone remodeling, such as Paget disease, rickets, osteomalacia, fractures, and malignant tumors.


Moderate elevation of ALP may be seen in other disorders such as Hodgkin disease, congestive heart failure, ulcerative colitis, regional enteritis, and intra-abdominal bacterial infections.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.



0-14 days: 83-248 U/L

15 days-<1 year: 122-469 U/L

1-<10 years: 142-335 U/L

10-<13 years: 129-417 U/L

13-<15 years: 116-468 U/L

15-<17 years: 82-331 U/L

17-<19 years: 55-149 U/L

> or =19 years: 40-129 U/L


0-14 days: 83-248 U/L

15 days-<1 year: 122-469 U/L

1-<10 years: 142-335 U/L

10-<13 years: 129-417 U/L

13-<15 years: 57-254 U/L

15-<17 years: 50-117 U/L

> or =17 years: 35-104 U/L



Liver 1%

0-6 years: 5.1-49.0%

7-9 years: 3.0-45.0%

10-13 years: 2.9-46.3%

14-15 years: 7.8-48.9%

16-18 years: 14.9-50.5%

> or =19 years: 27.8-76.3%

Liver 1

0-6 years: 7.0-112.7 IU/L

7-9 years: 7.4-109.1 IU/L

10-13 years: 7.8-87.6 IU/L

14-15 years: 10.3-75.6 IU/L

16-18 years: 13.7-78.5 IU/L

> or =19 years: 16.2-70.2 IU/L

Liver 2%

0-6 years: 2.9-13.7%

7-9 years: 3.7-12.5%

10-13 years: 2.9-22.3%

14-15 years: 2.2-19.8%

16-18 years: 1.9-12.5%

> or =19 years: 0.0-8.0%

Liver 2

0-6 years: 3.0-41.5 IU/L

7-9 years: 4.0-35.6 IU/L

10-13 years: 3.3-37.8 IU/L

14-15 years: 2.2-32.1 IU/L

16-18 years: 1.4-19.7 IU/L

> or =19 years: 0.0-5.8 IU/L

Bone %

0-6 years: 41.5-82.7%

7-9 years: 39.9-85.8%

10-13 years: 31.8-91.1%

14-15 years: 30.6-85.4%

16-18 years: 38.9-72.6%

> or =19 years: 19.1-67.7%


0-6 years: 43.5-208.1 IU/L

7-9 years: 41.0-258.3 IU/L

10-13 years: 39.4-346.1 IU/L

14-15 years: 36.4-320.5 IU/L

16-18 years: 32.7-214.6 IU/L

> or =19 years: 12.1-42.7 IU/L

Intestine %

0-6 years: 0.0-18.4%

7-9 years: 0.0-18.3%

10-13 years: 0.0-11.8%

14-15 years: 0.0-8.2%

16-18 years: 0.0-8.7%

> or =19 years: 0.0-20.6%


0-6 years: 0.0-37.7 IU/L

7-9 years: 0.0-45.6 IU/L

10-13 years: 0.0-40.0 IU/L

14-15 years: 0.0-26.4 IU/L

16-18 years: 0.0-12.7 IU/L

> or =19 years: 0.0-11.0 IU/L


Not present

Provides information to assist in interpretation of the test results

Total Alkaline Phosphatase:

Alkaline phosphatase (ALP) elevations tend to be more marked (more than 3-fold) in extrahepatic biliary obstructions (eg, by stone or cancer of the head of the pancreas) than in intrahepatic obstructions: the more complete the obstruction, the greater the elevation. With obstruction, serum ALP activities may reach 10 to 12 times the upper limit of normal, returning to normal upon surgical removal of the obstruction. The ALP response to cholestatic liver disease is similar to the response of gamma-glutamyltransferase (GGT) but more blunted. If both GGT and ALP are elevated, a liver source of the ALP is likely.


Among bone diseases, the highest level of ALP activity is encountered in Paget disease, because of the action of the osteoblastic cells as they try to rebuild bone that is being resorbed by the uncontrolled activity of osteoclasts. Values from 10 to 25 times the upper limit of normal are not unusual. Only moderate rises are observed in osteomalacia, while levels are generally normal in osteoporosis. In rickets, levels 2 to 4 times normal may be observed. Primary and secondary hyperparathyroidism are associated with slight to moderate elevations of ALP; the existence and degree of elevation reflects the presence and extent of skeletal involvement. Very high enzyme levels are present in patients with osteogenic bone cancer. A considerable rise in ALP is seen in children following accelerated bone growth.


ALP increases of 2 to 3 times normal may be observed in women in the third trimester of pregnancy, although the reference interval is very wide, and levels may not exceed the upper limit of normal in some cases. In pregnancy, the additional enzyme is of placental origin.


ALP Isoenzymes:

Liver ALP isoenzyme is associated with biliary epithelium and is elevated in cholestatic processes. Various liver diseases (primary or secondary cancer, biliary obstruction) increase the liver isoenzyme.


Liver 1  is increased in some nonmalignant diseases (such as cholestasis, cirrhosis, viral hepatitis, and in various biliary and hepatic pathologies). It is also increased in malignancies with hepatic metastasis, in cancer of the lungs and digestive tract, and in lymphoma.


An increase of liver 2  may occur in cholestasis and biliary diseases (eg, cirrhosis, viral hepatitis) and in malignancies (eg, breast, liver, lung, prostate, digestive tract) with liver metastasis.


Osteoblastic bone tumors and hyperactivity of osteoblasts involved in bone remodeling (eg, Paget disease) increase the bone isoenzyme. Paget disease leads to a striking, solitary elevation of bone ALP.


The intestinal isoenzyme may be increased in patients with cirrhosis and in individuals who are blood group O or B secretors.


The placental (carcino-placental antigen) and Regan isoenzyme can be elevated in cancer patients.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

No significant cautionary statements

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics 6th ed. Elsevier; 2018

2. Lowe D, Sanvictores T, John S. Alkaline phosphatase. In: StatPearls [Internet]. StatPearls Publishing; 2021. Updated August 11, 2021. Accessed November 10, 2021. Available at www.ncbi.nlm.nih.gov/books/NBK459201

3. Teitelbaum JE, Laskowski A, Barrows FP: Benign transient hyperphosphatasemia in infants and children: a prospective cohort. J Pediatr Endocrinol Metab. 2011;24(5-6):351-353

4. Jassam NJ, Horner J, Marzo-Ortega H, et al: Transient rise in alkaline phosphatase activity in adults. BMJ Case Rep. 2009;2009: bcr09.2009.2250

5. Verma J, Gorard DA: Persistently elevated alkaline phosphatase. BMJ Case Reports. 2012 Aug;24;2012:bcr2012006768

6. Sharma U, Pal D, Prasad R: Alkaline phosphatase: An overview. Indian J Clin Biochem. 2014 Jul;29(3):269-278

Method Description
Describes how the test is performed and provides a method-specific reference

Total Alkaline Phosphatase:

In the presence of magnesium and zinc ions, p-nitrophenyl phosphate is cleaved by phosphatases into phosphate and p-nitrophenol. The p-nitrophenol released is directly proportional to the catalytic alkaline phosphatase (ALP) activity. It is determined by measuring the increase in absorbance.(Package insert: Alkaline Phosphatase reagent. Roche Diagnostics; 02/2012)


ALP Isoenzymes:

Serum samples are electrophoresed through alkaline buffered (pH 9.1) agarose gels. Almost all ALP isoenzymes can be separated by electrophoresis according to their charge difference. However, because the electrophoretic mobilities of the liver and bone isoenzymes are quite similar, a modification is required for separation. The Sebia system utilizes differences between liver and bone isoenzyme sialation to achieve separation. Each sample is applied to the agarose gel in duplicate. One sample is passed through wheat germ lectin (wheat germ agglutin:WGA) and is deposited anodally from the point of sample application. The bone isoenzyme, which is rich in sialic acids, reacts with WGA and precipitates adjacent to the lectin application point. The separated isoenzymes are visualized using a specific chromogenic substrate, 5-bromo-4-chloro-3-indolyl phosphate/nitro blue tetrazolium in aminomethyl propanol (AMP) buffer, pH 10.0. The dried gels are read on a densitometer for the quantification of tissue isoforms.(Package insert: Sebia Hydragel 7 and 15 ISO-PAL. Sebia; 01/2017)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

2 to 5 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


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Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.



LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
ALKI Alkaline Phosphatase, Tot and Iso,S 24332-9
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
ALP Alkaline Phosphatase, S 6768-6
89503 Alkaline Phosphatase Isoenzymes, S 49243-9
45488 Liver 1 % 15348-6
57034 Liver 1 13874-3
45489 Liver 2 % 15349-4
57035 Liver 2 13875-0
45490 Bone % 15013-6
57036 Bone 1777-2
45491 Intestine % 15014-4
57037 Intestine 1778-0
29324 Placental 40793-2

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports