Alkaline Phosphatase

Additional Information:

UFHPL Epic order code: LAB112

CPT Code(s):


Specimen Requirements:

Type: Serum or plasma

Container/Tube: Serum gel or heparinized plasma

Sample Volume: Submit full tubes.

Minimum volume: 0.5 mL serum or plasma


  1. Send specimens in their original tubes.
  2. If there is a delay in transport of >1 hour, centrifuge tube.

Storage: Samples are stable for up to 4 days at 2 – 8ºC.

Unacceptable Conditions: Samples with moderate or marked hemolysis will be rejected.
Specimen Retention Time: 5 days


Measurements of serum alkaline phosphatase are used in the diagnosis of hepatobiliary disorders and bone disease associated with increased osteoblastic activity. Certain conditions such as Hodgkin’s Disease, congestive heart failure and ulcerative colitis will produce moderate elevation in alkaline phosphatase levels. Non-pathologic elevations can be observed in third trimester of pregnancy.


Alkaline phosphatase activity is determined by measuring the rate of conversion of p-nitro-phenylphosphate (pNPP) in the presence of 2-amino-2-methyl-1-propanol (AMP) at pH 10.4. The rate of change in absorbance due to the formation of pNP is measured bichromatically at 410/480 nm and is directly proportional to the ALP activity in the sample. (Package Insert, OSR General Chemistry, BAOSR6x04.03, 2014-04)


Within 24 hours

Reference Values:

Adult Males: 40-150 U/L

Adult Females 33-133 U/L