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Alpha-1-Antitrypsin Clearance, Feces and Serum

Reporting Name

Alpha-1-Antitrypsin Clearance

Useful For

Diagnosing protein-losing enteropathies

Necessary Information

Both feces and serum are required.

Specimen Required

Blood must be drawn during the stool collection period.


Specimen Type: Serum

Collection Container/Tube: Red top or serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL


Specimen Type: Stool

Supplies: Stool Containers - 24, 48, 72 Hours Kit (T291)

Specimen Volume: Entire collection

Collection Instructions:

1. Collect a 24-hour stool collection.

2. If no specimen is obtained in 24 hours, extend collection to 48 to 72 hours. Note time frame.

Specimen Type


Specimen Minimum Volume

Homogenized Stool: 1 mL; Serum: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Fecal Frozen (preferred) 14 days
  Ambient  14 days
  Refrigerated  14 days
Serum Frozen (preferred) 28 days
  Ambient  28 days
  Refrigerated  28 days

Day(s) and Time(s) Performed

Monday through Saturday; 2 p.m.

Seattle Children's Hospital Note:

TAT: 3 - 4 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

Method Name


Method Description

Nephelometry. Immunonephelometry quantitates the alpha-1-antitrypsin (A1A) contained in a 24-hour stool collection. From the concentration of stool A1A and serum A1A, a 24-hour clearance is calculated. In the absence of a serum specimen and/or a timed stool collection, an A1A stool concentration will be reported.(Instruction manual: Siemens Nephelometer II Siemens, Inc., Newark, DE)

Reference Values

Clearance: ≤27 mL/24 hours

Fecal alpha-1-antitrypsin concentration: ≤54 mg/dL

Serum alpha-1-antitrypsin concentration: 100-190 mg/dL

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82103 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CA1A Alpha-1-Antitrypsin Clearance 18271-7


Result ID Test Result Name Result LOINC Value
AAT24 Alpha-1-Antitrypsin, 24 Hr, F 46429-7
CRCLR Clearance In Process
AATS Alpha-1-Antitrypsin, S 6771-0

Reject Due To


Feces: NA

Serum: Mild OK; Gross OK


Feces: NA

Serum: Mild OK; Gross OK


Feces: NA

Serum: Mild OK; Gross OK


Stool collected in any preservative or fixative

Profile Information

Test ID Reporting Name Available Separately Always Performed
CA1A_ Clearance No Yes
A1A24 Alpha-1-Antitrypsin, 24 Hr, F No Yes


If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request Form (T728) with the specimen (