Skip to content

Alpha-1 Antitrypsin Normalized Clearance, Serum/Plasma and Stool

Published: August 9, 2026Updated: August 16, 2026

A calculated test using alpha-1 antitrypsin measurements from blood and stool to help assess protein loss through the digestive tract.

Quick summary

["This test can help identify excess protein loss through the intestines, which may occur with several gastrointestinal conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
93419-0
Short code
A1AT Cl Pnl SerPl+Stl
Synonyms
A1AT Cl Pnl SerPl+Stl
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

Alpha-1 antitrypsin clearance is a calculated result based on alpha-1 antitrypsin levels in serum or plasma and in a timed stool collection. It helps assess whether protein is being lost abnormally through the digestive tract.

Why might I need this test?

A clinician may order this test when symptoms suggest protein-losing enteropathy, a group of conditions in which the intestines lose too much protein. It may be considered in people with unexplained swelling, low blood protein, or gastrointestinal symptoms such as persistent diarrhea.

How is the test performed?

A blood sample is used to measure the alpha-1 antitrypsin level in serum or plasma. You also collect stool for a specified period, usually at least 24 hours, and the laboratory combines the measurements to calculate the clearance result.

How do I prepare for the test?

Follow the stool-collection instructions provided by the laboratory, including the required collection time and whether a diet restriction is needed. Collect all stool during the specified period and avoid contaminating it with urine or toilet water. Ask the laboratory whether medications should be temporarily held.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Alpha-1 antitrypsin clearance

Frequently asked questions

Does this test diagnose alpha-1 antitrypsin deficiency?
Not by itself. This clearance test evaluates protein loss through the intestines, whereas alpha-1 antitrypsin deficiency is usually assessed using blood testing and, when needed, genetic or protein-analysis testing.
Why is a timed stool collection required?
The amount of protein lost in stool depends on both the stool concentration and the total amount collected. A complete, accurately timed collection allows the laboratory to calculate a reliable clearance result.
What if the stool collection is incomplete or spills into the toilet?
An incomplete or contaminated collection can make the result inaccurate. Contact the laboratory or ordering clinician for instructions on recollecting the sample if a problem occurs.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy