Test ID: GIAR
Giardia Antigen, Feces
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Screening for the detection of Giardia antigens present in stool specimens.
See Parasitic Investigation of Stool Specimens Algorithm in Special Instructions for other diagnostic tests that may be of value in evaluating patients with diarrhea.
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
See Parasitic Investigation of Stool Specimens Algorithm in Special Instructions.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
Enzyme-Linked Immunosorbent Assay (ELISA)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Forms: If not ordering electronically, submit a Microbiology Request Form (Supply T244) with the specimen.
Submit only 1 of the following specimens:
Specimen Type: Preserved stool
Container/Tube:
Preferred: Stool container with 10% buffered formalin preservative (Supply T466)
Acceptable: SAF or MF
Specimen Volume: 5 g
Specimen Stability Information: Ambient (preferred)/Refrigerated
Specimen Type: Unpreserved stool
Container/Tube: Stool container (Supply T288)
Specimen Volume: 5 g
Collection Instructions: See Stool Collection Information Sheet in Special Instructions.
Specimen Stability Information: Frozen
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | Duodenal, duodenal aspirate, or small bowel aspirate (this test is not U.S. FDA approved for these types of sources); grossly bloody stool (containing no visible stool), or very mucoid stool |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Fecal | Varies | |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Giardia lamblia are flagellated protozoa which can be found contaminating natural streams, lakes, and surface water municipal reservoirs. The human host ingests them in water, food, and by the fecal-oral route.
Giardia infect primarily the small intestine causing diarrhea by unknown mechanisms after attaching by their ventral sucker. Malabsorption may also occur.
Giardiasis is the most common intestinal parasitic infection in the United States and is a common cause of diarrhea in children (especially in day care centers), travelers, and in waterborne epidermics.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Negative
Interpretation Provides information to assist in interpretation of the test results
A positive enzyme-linked immunosorbent assay (ELISA) indicates the presence in a stool specimen of Giardia lamblia antigens.
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.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Small numbers of Giardia residing only in the duodenum may not yield a positive enzyme-linked immunosorbent assay (ELISA).
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 3 consecutive stool specimens is recommended before considering the results negative.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Janoff EN, Craft JC, Pickering LK, et al: Diagnosis of Giardia lamblia infections by detection of parasite-specific antigens. J Clin Microbiol 1989;27:431-435
Method Description Describes how the test is performed and provides a method-specific reference
Giardia antigens present in the stool supernatant are captured by antibodies coating the wells of a microtiter plate. The bound antigen is "sandwiched" by the addition of a second antibody and the signal is amplified through the use of biotin-strepavidin horseradish peroxidase. Blue color develops with the presence of bound antigen. The reaction is stopped with the addition of acid and read visually or with the aid of a spectrophotometer. (Rosenblatt JE, Sloan LM, Schneider SK: Evaluation of an enzyme-linked immunosorbent assay for the detection of Giardia lamblia in stool specimens. Diagn Microbiol Infect Dis 1993;16:337-341)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 1 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
87329
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 24085 | Giardia Ag, F | 6412-1 |
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