Aspartate Aminotransferase (AST)

Label Mnemonic:	AST
Epic code:	LAB131
Order form:	Laboratory Requisition
Supply order:	Supply Order Form
Billing:	Billing Policies
CPT code:	84450

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 tube or 1 light green top Microtainer^® for pediatric patients

Testing Schedule:

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

Turn Around Time:

1 hour (upon receipt in laboratory)

Reference Range:

Males; 0-40 U/L
Females; 0-32 U/L

Pediatric Ranges:
Age               Male/Female U/L
1-3 years              10-50
4-6 years              10-45
7-12 years             10-40
13-18 years            10-35

Comments:

Avoid hemolysis. Adult reference ranges changed 11/26/2013.

Test Limitations:

Criterion: Recovery within plus or minus 10% of initial value.

Hemolysis interferes due to AST activity from erythrocytes (index of 
50).

Icterus: No significant interference up to an I index of 60 
(approximate conjugated and unconjugated bilirubin concentration: 60 
mg/dL).

Lipemia (Intralipid): No significant interference up to an L index of 
250 (approximate triglycerides concentration: 500 mg/dL). There is 
poor correlation between turbidity and triglycerides concentration. 
Lipemia may cause absorbance flagging as a result of an absorbance 
increase.

Reference
Glick MR, Ryder KW, Jackson SA. Graphical Comparisons of Interferences 
in Clinical Chemistry Instrumentation. Clin Chem 1986;32:470-474.

Methodology:

Spectrophotometric

Sample Processing:

Centrifuge at a speed and time necessary to get barrier separation of plasma/serum and cells within 1 hour of collection. Send specimen in original tube. Do Not transfer to another tube.
Each sample must be labeled with at least TWO full patient identifiers (First/Last Name & DOB are sufficient for non-UIHC affiliated clients) to avoid sample rejection/delays.

Sample Storage:

Refrigerate.
All sample storage requirements are intended for delivery to UIHC within 24 hours of collection for testing. If samples won't arrive in this time period, please call the UIHC Core Lab for alternative storage/shipping instructions (319-356-3527).

Transport Instructions:

Place labeled specimen into zip-lock type biohazard bag; seal bag.
Place completed requisition into outside pocket of bag.
Transport in cooler with refrigerated coolant packs.