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Asparate Aminotransferase (AST)

Test Codes

Antrim #17264, EPIC: LAB5011, AST

Department

Chemistry

Specimen Collection Criteria

FOR EC AND INPATIENT SAMPLE COLLECTION ONLY:

Preferred Sample:  One Light Green (Mint) Top Plasma Separator Tube (PST). (Minimum Whole Blood: 4.0 mL) 

Acceptable Sample:  One Gold Top SST (Minimum Whole Blood: 4.0 mL) 

Do NOT use Dark Green-top Lithium or Sodium Heparin tubes.

FOR PHYSICIAN OFFICE/OUTREACH SAMPLE COLLECTION:

COLLECT:  One Gold Top SST (Minimum Whole Blood:  4.0 mL) 

Contact Laboratory for acceptability of other tube types.
See Minimum Pediatric Specimen Requirements for Microtainer^® collection.

Physician Office/Draw Specimen Preparation

Let SST specimens clot 30–60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2–8°C or 36–46°F) the centrifuged SST tube within two hours of collection. (Minimum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged SST tube, refrigerated (2–8°C or 36–46°F). (Minimum: 0.5 mL)

Rejection Criteria

Moderate to grossly hemolyzed specimens (due to in vitro hemolysis).

Red-top tubes with serum not separated from cells within two hours of collection.

In-Lab Processing

Let SST specimens clot 30-60 minutes. Centrifuge SST tubes and Microtainers^® to separate serum from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gel
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gel
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20–26°C or 68–78.8°F): 2–4 hours
Refrigerated (2–8°C or 36–46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2–8°C or 36–46°F): 7 days

Laboratory

Canton Chemistry Laboratory
Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory 
Grosse Pointe Chemistry Laboratory 
Livonia Main Laboratory
Lenox Main Laboratory
Royal Oak Automated Chemistry Laboratory 
Troy Chemistry Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Wayne Chemistry Laboratory 

Performed

Sunday – Saturday, 24 hours a day.
STAT results available within 1 hour of receipt in the Laboratory.
Routine results available within 4 hours.

Reference Range

<35 U/L.

Test Methodology

Enzymatic.

Interpretation

Elevated AST occurs with hepatocyte damage (rather than obstructive liver disease) including viral toxic hepatitis, cirrhosis, hepatic congestion and fatty liver. A normal AST does not exclude cirrhosis. An aspartate aminotransferase to alanine aminotransferase (AST/ALT) ratio of greater than 2 suggests alcoholic hepatitis rather than viral hepatitis. Increased AST levels also occur following myocardial infarction, skeletal muscle disease and hemolysis (in vivo or in vitro).

Clinical Utility

The quantitative determination of AST (aspartate aminotransferase) aids in the diagnosis and management of certain types of liver disease. AST is no longer recommended for diagnosis of myocardial infarction.

CPT Codes

84450, 1920-8

Contacts

Last Updated

3/21/2023