Giardia Antigen, Stool (Sendout)

Interpretation

Guidelines

• Washington DOH Notifiable Conditions

Method

Enzyme-Linked Immunosorbent Assay (ELISA)

Reference Range

Female		Male
Age	Range	Age	Range
0-	Negative [NRN]	0-	Negative [NRN]

Effective date: 05/01/2019

Ref. Range Notes

Reference Values: Negative

Interpretation:

A positive enzyme-linked immunosorbent assay (ELISA) indicates the presence in a fecal specimen of Giardia antigens.

As per the manufacturer, the assay has a sensitivity of 96%, specificity of 97%, and a positive predictive value of 95%.

Interpretation of results should be correlated with patient symptoms and clinical picture.

Interferences and Limitations

Cautions:

Small numbers of organisms residing only in the duodenum may not yield a positive test result.

Giardia antigen detection should be used as an aid in diagnosis of giardiasis. A single diagnostic assay should not be used as the only criteria to form a clinical conclusion.

Testing of at least 2 consecutive fecal specimens by enzyme-linked immunosorbent assay (ELISA) is recommended before considering the results negative.

Feces containing large amounts of leukocytes or red blood cells may give falsely positive results.

References

1. Mayo Clinic Laboratories Giardia Antigen, Feces Clinical & Interpretive Information.

Ordering & Collection

Specimen Type

Stool

Collection

Collect 5 g of stool in a screw-capped, preservative-free plastic container.

• Also Accepted: 5 g of stool in Formalin-Meridian 10% Buffered Neutral preservative or SAF (sodium acetate formalin).

Unacceptable:

• Stool in Cary-Blair preservative.
• Duodenal, colonic wash, or small bowel aspirates are not acceptable for this test.

Handling Instructions

Outside Laboratories:

• Unpreserved Stool: Freeze sample at -20°C.
• Stool in preservative: Store and transport at ambient temperature.

Stability:

• Unpreserved Stool: Frozen (preferred): 60 days; Refrigerated: 8 hours; Ambient: 8 hours.
• Stool in Preservative: Ambient (preferred): 60 days; Frozen (not preferred): 60 days; Refrigerated: Unacceptable.

Reject Due To: Grossly bloody feces (containing no visible specimen), or very mucoid feces, specimens preserved in ECOFIX (green cap), C and S (orange cap), or methiolate formalin (MF).

Quantity

Requested: 5 g Stool
Minimum: 2 g Stool

Processing

Receiving Instructions

• Unpreserved Stool: Freeze at -20°C.
• Stool in Preservative: Store and transport at ambient temperature. Add SRRT (Specimen Received at Room Temp) to the modifier at login.

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. Separate stool specimens or aliquots must be submitted for each sendout test.

• 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.

Sendouts:

• Order Mayo Test: GIAR
• Interfaced: Yes [Interface: 601; Worksheet: MAFZ]

Stability:

• Unpreserved Stool: Frozen (preferred): 60 days; Refrigerated: 8 hours; Ambient: 8 hours.
• Stool in Preservative: Ambient (preferred): 60 days; Frozen (not preferred): 60 days; Refrigerated: Unacceptable.

Reject Due To: Grossly bloody feces (containing no visible specimen), or very mucoid feces, specimens preserved in ECOFIX (green cap), C and S (orange cap), or methiolate formalin (MF).

Misc Sendout

Performance

Lab Department

Sendouts Mayo Lab (FZ)(MAFZ)

Frequency

Performed: Mon-Sat. Maximum Laboratory Time: 4 days

Available STAT?

No

Performing Location(s)

Sendout	Mayo Clinic Laboratories 800-533-1710 200 First Street Southwest Rochester, MN 55901

Billing & Coding

CPT Codes

87329

LOINC

6412-1

Interfaced Order Code

UOW3881

Interfaced Result Code

UOW3881