Lab Test

Alkaline Phosphatase (ALP)

Alk Phos

Test Codes

Antrim #17265, EPIC: LAB5006, SOFT: ALP

Specimen Collection Criteria


Preferred Sample:  One Light Green Top Plasma Separator Tube (PST) (Minimum Whole Blood: 4.0 mL)

Acceptable Sample:  One Gold Top SST (Minimum Whole Blood:  4.0 mL)


COLLECT:  One Gold Top SST (Minimum Whole Blood:  4.0 mL) 

Contact Laboratory for acceptability of other tube types. 
See Minimum Pediatric Specimen Requirements for Microtainer® collection.

Physician Office/Draw Specimen Preparation

Let SST specimens clot 30–60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2–8°C or 36–46°F) the centrifuged SST tube within two hours of collection. (Minimum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged SST tube, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Rejection Criteria

  • Moderate to grossly hemolyzed specimens.
  • Red-top tubes with serum not separated from cells within two hours of collection.

In-Lab Processing

Let SST specimens clot 30-60 minutes. Centrifuge SST tubes and Microtainers® to separate serum from cells. Deliver immediately to the appropriate testing station.


Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers® with Separator Gel
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers® without Separator Gel
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2–8°C or 36–46°F): 7 days


Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak Automated Chemistry Laboratory
Troy Chemistry Laboratory


Sunday – Saturday, 24 hours a day.
Results available within 4 hours.

Reference Range

 Age  Male (U/L)   Female (U/L)
0 – 14 Days  90 – 273 90 – 273
15 Days – < 1 Year 134 – 518 134 – 518
1 – 9 Years 156 – 369 156 – 369
10 – 12 Years 141 – 460 141 – 460
13 – 14 Years 127 – 517 62 – 280
15 – 16 Years      89 – 365 54 – 128
17 – 18 Years 59 – 164 48 – 95
> 19 Years 33 – 120 33 – 120
> 60 Years   37 – 135

Test Methodology



  • Serum alkaline phosphatase (AP) levels in children are higher than those in adults; levels are also higher (up to 5-6 times normal) in late pregnancy due to release of AP from the placenta. Slight increases in AP may be seen following a fatty meal (due to release of the intestinal isoenzyme) in patients who have type O or B blood types and who are Lewis positive secretors.
  • Increases of AP are associated with a variety of disorders affecting the bone. These include healing fractures, primary and secondary tumors (only occasionally in multiple myeloma), Paget's disease, rickets and osteomalacia, and in later stages of primary hyperparathyroidism. Increased AP is associated with many cholestatic liver diseases (e.g. intra or extra-hepatic biliary obstruction), infiltrative liver disease (sarcoidosis, TB, abscess), liver metastases, hepatitis (transaminase increases are significantly greater than AP), cholangitis, cirrhosis, drug treatment (including erythromycin, methyltestosterone, large doses of estrogens, phenothiazines).
  • If necessary, measurement of Gamma Glutamyl Transpeptidase or 5' Nucleotidase may help distinguish liver and bone disease. These two enzymes would generally be increased in liver disease, but not in bone disease. Determination of AP isoenzymes may also be useful to determine the cause of an elevated AP.
  • AP may also be slightly increased in a variety of conditions not affecting liver or bone such as congestive heart failure, pulmonary infarction, malignancy with production of placental-like AP by the tumor and severe infections. Transient hyperphosphatasemia of infancy may be associated with AP levels that are several times the upper limit of normal.

Clinical Utility

The quantitative determination of alkaline phosphatase activity aids in the diagnosis and management of liver and bone diseases.

CPT Codes



Last Updated


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This directory currently reflects information only for specimens collected and/or processed at the
Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.