Alpha 1 Antitrypsin, Feces

Alpha-1-Antitrypsin, Alpha 1 Antitrypsin, Random Stool

Test Codes

EPIC: LAB1232170, Beaker: Alpha-1-Anti, Quest: 14628

Department

Send Outs

Instructions

Collect fresh stool in a plastic leak-proof container. Adult and older children patients can collect the specimen by passing feces into plastic wrap stretched loosely over the toilet bowl. Then transfer 10.0 g of the stool specimen into the plastic container. With young children and infants wearing diapers, the diaper should be lined with clean plastic wrap to prevent absorption. A pediatric urine bag can be attached to the child to ensure that the stool specimen is not contaminated with urine. Then transfer 10.0 g of the stool specimen from the plastic lined diaper to the plastic container. Do not submit the diaper itself. Freeze and ship frozen.

Specimen Collection Criteria

Collect: 10.0 grams random stool specimen in a sterile collection container.

Physician Office/Draw Specimen Preparation

Maintain specimen frozen (-20°C/-4°F or below) prior to transport.

Preparation for Courier Transport

Transport: 10.0 grams, random stool, frozen (-20°C/-4°F or below).

Rejection Criteria

Fecal collected in any preservative or fixative.

In-Lab Processing

Maintain specimen frozen (-20°C/-4°F or below) prior to transport.

Transport: 10.0 grams, random stool, frozen (-20°C/-4°F or below). 

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 8 days
Frozen (-20°C/-4°F or below): 28 days

Specimen Storage in Department Prior to Disposal: 

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Quest Diagnostics, Wood Dale, IL.

Performed

Daily.
Results available in 2-4 days.

Reference Range

<55 mg/dL.

Test Methodology

Nephelometry.

Interpretation

By report.

Clinical Utility

This test measures alpha-1-antitrypsin (AAT) concentration in a random stool specimen and may help screen for protein-losing enteropathy [1]. An AAT level measured in a 24-hour stool specimen and interpreted jointly with a simultaneous blood AAT level is generally preferred for the diagnosis of protein-losing enteropathy [2].

Protein-losing enteropathy is a disorder caused by inflammation or destruction of intestinal mucosa and subsequent increased loss of plasma protein through the gastrointestinal tract. Conditions associated with protein-losing enteropathy include but are not limited to inflammatory bowel disease, lymphoma, Whipple disease, systemic lupus erythematosus, and food allergies [3]. Measurement of radioactive albumin is the "gold standard" for gastrointestinal protein loss but is rarely performed because of the high cost and complex methodology [4]. AAT has a molecular weight similar to that of albumin and is resistant to proteolysis. Therefore, the excretion of AAT in stool can be used to estimate protein loss in the gastrointestinal tract [2,3].

Low stool AAT levels may also be caused by AAT deficiency or impaired hepatic synthesis of AAT; thus, they must be interpreted in conjunction with plasma AAT levels [3]. Abnormal results in patients with intestinal blood loss need to be interpreted carefully owing to the possibly increased AAT clearance [4].

An AAT level measured in a random stool specimen may not accurately reflect daily AAT excretion [2]. AAT clearance, calculated from AAT concentrations in a 24-hour fecal specimen and a serum specimen, is more reliable for estimating protein loss [5].

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

CPT Codes

82103

Contacts

Last Updated

12/17/2025