Can this result diagnose a condition on its own?

No. Laboratory results are interpreted with symptoms, medical history, specimen conditions and related tests.

Which reference range should I use?

Start with the performing laboratory's own reference interval; clinical cutoffs, when relevant, are separate sourced thresholds used for a specific purpose.

When should I discuss the result with a healthcare professional?

Results that are clearly outside range, persistent, symptomatic or unexpected should be reviewed by a healthcare professional.

Information about a laboratory test

ALP in Children: How Is It Interpreted?

ALP can be physiologically higher in children because of growth and bone formation, so an age-appropriate pediatric reference interval is needed.

Test summary

Test name: ALP
Abbreviations: ALP, ALKP
Category: Hepatology / Bone & Cholestatic Enzymes
Panel: Liver Function Panel / Bone Metabolism
Specimen: Serum / plasma
Common units: U/L, µkat/L

What does the test measure?

Measures alkaline phosphatase enzyme activity in blood; major clinical sources include liver/bile ducts and bone.

Why is the test ordered?

Used to assess hepatobiliary and bone-related conditions, often together with GGT and other tests.

Information about a low result

Low ALP is less common and may be associated with nutritional, mineral or other conditions; it is not diagnostic by itself.

Information about a high result

High ALP may be hepatobiliary or bone-related. Physiologic elevations can also occur during growth in children and in pregnancy.

Reference and clinical context

Start with the performing laboratory's reference interval, unit and specimen conditions. Numeric information on this page is stored as sourced example intervals or clinical thresholds.

Reference range 1

>= 20 – <= 130 U/L

Population: Adults
Age range: 18
Specimen: Serum / plasma

Example adult ALP reference interval

The source presents these values as a common example reference interval. Laboratory method, age and clinical context can change the range; the user's own report takes priority.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

GGT, other liver tests and sometimes ALP isoenzymes help identify the likely source. Age and pregnancy can change interpretation.

Related specialties

Gastroenterology
Internal Medicine
Pediatrics
Endocrinology

Frequently asked questions

Sources

Liver Function Tests — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Liver panel components, purposes, pattern-based interpretation and limitations · Verified: Aug 12, 2026
Comprehensive Metabolic Panel — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Example adult intervals for ALT, AST, ALP, albumin, bilirubin, total protein, BUN, creatinine and electrolytes · Verified: Aug 12, 2026
Gamma-glutamyl Transferase (GGT) Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · GGT purpose and interpretation with ALP and other liver tests · Verified: Aug 12, 2026
ALP - Blood Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · ALP tissue sources, adult example interval and bone/liver interpretation · Verified: Aug 12, 2026