Alkaline Phosphatase and Isoenzymes


Core Lab Study

Alk Phos, ALP and fractionation, heat-stable ALP.

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/GenderTotal ALP Conventional and SI UnitsBone Fraction Conventional and SI UnitsLiver Fraction Conventional and SI Units
  Male75–375 units/LNANA
  Female65–350 units/LNANA
1–8 yr
  Male70–364 units/L50–319 units/LLess than 8–76 units/L
  Female73–378 units/L56–300 units/LLess than 8–53 units/L
9–12 yr
  Male112–476 units/L78–339 units/LLess than 8–81 units/L
  Female98–448 units/L78–353 units/LLess than 8–62 units/L
13–14 yr
  Male112–476 units/L78–389 units/LLess than 8–48 units/L
  Female56–350 units/L28–252 units/LLess than 8–50 units/L
15 yr
  Male70–378 units/L48–311 units/LLess than 8–39 units/L
  Female42–168 units/L20–115 units/LLess than 8–53 units/L
16 yr
  Male70–378 units/L48–311 units/LLess than 8–39 units/L
  Female28–126 units/L14–87 units/LLess than 8–50 units/L
17 yr
  Male56–238 units/L34–190 units/LLess than 8–39 units/L
  Female28–126 units/L17–84 units/LLess than 8–53 units/L
  Male35–142 units/L11–73 units/L0–93 units/L
  Female25–125 units/L11–73 units/L0–93 units/L
ALP levels vary by age and gender; values in children are higher than in adults because of the level of bone growth and development. Values may be slightly elevated in older adults.

Critical Findings and Potential Interventions

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