Alpha 1 Antitrypsin, Random Stool (Sendout)

Interpretation:

Patients with protein-losing enteropathies generally have alpha-1-antitrypsin fecal concentrations over 100 mg/dL.

Borderline elevations above the normal range are equivocal for protein-losing enteropathies.

Cautions:

The clearance studies using 24-hour fecal specimens and serum determinations are preferred as it normalizes the large range of serum alpha-1-antitrypsin (AAT) concentrations and the variability in random fecal AAT concentrations. In the absence of either a 24-hour fecal collection or a contemporary serum specimen, the fecal concentration of AAT can be used as a surrogate marker.

When gastric loss of AAT is suspected (eg, Menetrier disease), AAT clearance is not a reliable indicator of protein loss as AAT is sensitive to pH <3 and is rapidly destroyed. When gastric protein loss is suspected and the AAT clearance is normal, the recommendation is to repeat testing after starting an acid suppressive medication regime.

Outside Laboratories:

• Freeze stool at -20°C. If other tests are requested, submit a separate specimen for each.

Stability: Frozen (preferred): 14 days; Ambient: 14 days; Refrigerated: 14 days.

Reject Due To: Feces collected in any preservative or fixative.

Freeze stool at -20°C.

• If a single unpreserved stool specimen is received for multiple tests, samples may be sent to Micro to be split prior to freezing. Include CID labels and directions for splitting (including minimum volumes). If there is insufficient sample, contact the provider to prioritize testing.

SPS Login Note: This test should be ordered on its own accession to prevent multiple stool tests from routing to the same container ID in Sunquest and to ensure proper interface batching. Separate stool specimens or aliquots must be submitted for each sendout test.

Sendouts:

• Order Mayo Test: A1AF.
• Interfaced: Yes.

Stability: Frozen (preferred): 14 days; Ambient: 14 days; Refrigerated: 14 days.

Reject Due To: Feces collected in any preservative or fixative.