Alkaline phosphatase

ChemistryAlso known as: ALPAlso known as: Alkaline phosphomonoesteraseAlso known as: Alkaline PhosU/L

Measures alkaline phosphatase enzyme levels indicating bone and liver metabolism.

Normal Range
44 – 121
U/L
Abnormal Levels
< 44 U/L
> 121 U/L
Specimen Type
Blood

Why This Biomarker Matters

ALP elevation suggests bone turnover or liver/bile duct dysfunction. Abnormal results can prompt investigation for bone disease, liver disease, or nutritional deficiencies affecting mineral metabolism.

Optimal Ranges

Clinician-defined 4-point reference thresholds (U/L)

Default Range

44
44
121
121
Low
44 U/L
Borderline Low
44 U/L
Optimal
121 U/L
Borderline High
121 U/L

Overview

Alkaline phosphatase (ALP) is an enzyme found in bones, liver, and intestines. It plays a role in bone formation and bile production. This test measures ALP levels to assess bone metabolism and liver function. Elevated ALP can indicate bone disease (osteoporosis, fractures, or Paget's disease), liver disease, or bile duct obstruction. Low levels are less common but may suggest nutritional deficiencies or genetic conditions. ALP is often part of routine health screening or organ function assessment.

Research & Evidence

100 publications

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Research data from MEDLINE/PubMed · 100 articles

Technical Information (LOINC Codes)

Standardized laboratory codes for this biomarker

6768-6Primary
Alkaline phosphatase [Enzymatic activity/volume] in Serum or Plasma
U/L
29639-2
Alkaline phosphatase [Enzymatic activity/mass] in Tissue
U/g
40410-3
Alkaline phosphatase [Enzymatic activity/volume] in Peritoneal fluid
U/L
34568-6
Alkaline phosphatase [Presence] in Body fluid
77141-0
Alkaline phosphatase [Enzymatic activity/volume] in Serum, Plasma or Blood
U/L
1783-0
Alkaline phosphatase [Enzymatic activity/volume] in Blood
U/L
15148-0
Alkaline phosphatase [Enzymatic activity/volume] in Body fluid
U/L
1775-6
Alkaline phosphatase [Mass/volume] in Body fluid
ug/L
54907-1
Alkaline phosphatase [Enzymatic activity/volume] in Amniotic fluid
U/L
55971-6
Alkaline phosphatase [Enzymatic activity/volume] in Cord blood
U/L
59164-4
Alkaline phosphatase [Enzymatic activity/volume] in Dialysis fluid
U/L
16337-8
Alkaline phosphatase [Enzymatic activity/volume] in Urine
U/L
1776-4
Alkaline phosphatase [Mass/volume] in Urine
ug/L