Alkaline Phosphatase
Alkaline phosphatase has a broader age gradient than the transaminases, with the distribution shifting upward in older adults because ALP reflects both hepatobiliary and bone turnover processes.
Unit: U/L · 12 groups · age and sex · 1 source
Filed under panels: Liver Function , Metabolic Panel · topics: Liver , Metabolic
Alkaline Phosphatase by age and sex
| Age (years) | Males (U/L) | Females (U/L) |
|---|---|---|
| 20-29 | median 72 middle 90% 47.3 to 106.2 | median 66 middle 90% 41 to 105.4 |
| 30-39 | median 69 middle 90% 45 to 110.7 | median 64 middle 90% 37 to 107 |
| 40-49 | median 69 middle 90% 44 to 117.3 | median 67 middle 90% 41 to 111.1 |
| 50-59 | median 73 middle 90% 47 to 113 | median 81 middle 90% 48 to 126 |
| 60-69 | median 74 middle 90% 47 to 119 | median 80 middle 90% 52 to 130 |
| 70+ | median 74 middle 90% 48 to 125 | median 80 middle 90% 48 to 129 |
Download Alkaline Phosphatase percentiles (CSV) Values at full stored precision; tables on this site may round for display. Licensed under CC BY 4.0.
Population Distribution
Alkaline phosphatase (ALP) is a chemistry-panel enzyme derived mainly from liver and bone, with smaller contributions from intestine and placenta. Population distributions therefore reflect both cholestatic liver processes and age-related changes in bone remodeling. These NHANES percentiles describe the full US population rather than a screened healthy subgroup.
Frequently Asked Questions
Why does ALP rise in older adults?
ALP reflects both biliary processes and bone turnover. Age-related changes in bone remodeling, medication use, cholestatic disease, and frailty all broaden the upper half of the distribution later in life.
Is ALP liver-specific?
No. ALP comes from both liver and bone, so an elevated value is less specific than ALT or AST without additional context such as GGT or ALP isoenzymes.
Why is ALP useful alongside GGT?
When ALP is elevated, GGT can help distinguish a hepatobiliary source from a bone-predominant source because GGT rises with biliary and liver disease but not with most bone conditions.
Data Sources
Cite this data
LabNorms. Alkaline Phosphatase population percentiles by age and sex. Data: NHANES 2017-March 2020 Pre-Pandemic. https://labnorms.com/analytes/alkaline-phosphatase/. Licensed under CC BY 4.0. Accessed [date].
Download Alkaline Phosphatase percentiles (CSV) Values at full stored precision; tables on this site may round for display. Licensed under CC BY 4.0.