Alanine Aminotransferase (ALT with P5P)

Label Mnemonic:	ALT
Epic code:	LAB132
Downtime form:	Doctor/Provider Orders - Pathology Core and Specialty Care Nursery

Chemistry
6240 RCP
356-3527

Specimen(s):

Plasma

Collection Medium:

Plasma Separator Tube 4.5 mL

Alternate Collection Media:

Call laboratory for additional acceptable specimen collection containers.

Minimum:

3 mL; light green top or 1 Microtainer®

Testing Schedule:

24 hrs/day, 7 days a week, including holidays.

Turn Around Time:

1 hour (upon receipt in laboratory)

Reference Range:

Adult Male: 0-50 U/L

Adult Female: 0-35 U/L

Pediatric Ranges:

Age	ALT (U/L)
Up to 1 year	7-36
1-12 years	12-28
13-18 years (female)	10-25
13-18 years (male)	12-27

Comments:

Effective 2/25/2025, ALT activity is measured using an assay supplemented with pyridoxal-5’-phosphate (P5P), a required co-factor for measuring ALT activity. ALT results from P5P supplemented assays are approximately 20 – 30% higher than results from non-supplemented assays. ALT values should always be interpreted in conjunction with clinical history, physical examination findings, and, if applicable, data from other diagnostic tests.

This test is also performed in the Iowa River Landing (IRL) clinical laboratory (for specimens drawn at that site).

This test is also performed in the North Dodge clinical laboratory (for specimens drawn at that site).

Test Limitations:

Hemolysis interferes due to ALT activity from erythrocytes and should be avoided. ALT will not be reported for specimens with severe enough hemolysis (100 – 500 mg/dL hemoglobin depending on ALT activity).

The assay is unaffected by icterus (bilirubin less than 60 mg/dL) and lipemia (Intralipid less than 150 mg/dL). Criterion: recovery within 10% of initial value.

Methodology:

Spectrophotometric with pyridoxal phosphate activation

CPT Code:

84460