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HelpTest Code LAB8944 Aspergillus (Galactomannan) Antigen, Serum
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Aspergillus Ag, SSpecimen Type
Serum SSTOrdering Guidance
For bronchoalveolar lavage specimens, order ASPBA / Aspergillus Antigen, Bronchoalveolar Lavage.
Specimen Required
Container/Tube: Serum gel (red-top tubes are not acceptable)
Specimen Volume: 1.5 mL Serum
Collection Instructions:
1. Avoid exposure of specimen to atmosphere to prevent sample contamination from environment.
2. Centrifuge and send specimen in original serum gel collection tube. Do not aliquot serum or open tube.
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum SST | Refrigerated (preferred) | 14 days | SERUM GEL TUBE |
| Frozen | 14 days | SERUM GEL TUBE |
Specimen Minimum Volume
Serum: 1 mL
Day(s) Performed
Monday through Friday, Sunday
Specimen Retention Time
2 weeksReport Available
1 to 4 daysReference Values
<0.5 index
Reference values apply to all ages.
Useful For
Aiding in the diagnosis of invasive aspergillosis
Assessing response to therapy
CPT Code Information
87305
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ASPAG | Aspergillus Ag, S | 44357-2 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 84356 | Aspergillus Ag, S | 44357-2 |
Method Description
The Platelia Aspergillus enzyme immunoassay (EIA) is a 1-stage immunoenzymatic sandwich microplate assay that detects galactomannan in human serum. The assay uses the rat monoclonal antibody EBA-2, which is directed against Aspergillus galactomannan. The monoclonal antibody is used to coat the wells of the microplate and bind the antigen and as the detector antibody in the conjugate reagent (peroxidase-linked monoclonal antibody).
Serum samples are heat-treated in the presence of EDTA to dissociate immune complexes and to precipitate serum proteins that could possibly interfere with the test. The treated serum samples and conjugate are added to the wells coated with the monoclonal antibody and incubated. A monoclonal antibody-galactomannan-monoclonal antibody/peroxidase complex is formed in the presence of Aspergillus antigen.
The strips are washed to remove any unbound material, and the substrate solution is added, which will react with the complex bound to the well to form a blue color reaction. The enzyme reaction is stopped by the addition of acid, which changes the blue color to yellow. The optical absorbance of specimens and controls is determined with a spectrophotometer set at 450 nm and 620/630 nm wavelengths.
Negative, cutoff (low-positive), and high-positive controls are analyzed each time the assay is performed. The presence or absence of Aspergillus galactomannan antigen in the test sample is determined by calculation of an index for the specimen. The index is the optical density (OD) value of the specimen divided by the mean OD of wells containing the cutoff control serum (low-positive control).(Package insert: Platelia Aspergillus EIA. Bio-Rad Laboratories; 10/2020)
Supportive Data
In clinical studies submitted for the US Food and Drug Administration-approval process, the sensitivity of the test was reported to be 81% for proven/provable invasive aspergillosis (N=31 patients), and the specificity was 89% (N=148 patients). The positive and negative predictive values were reported as 68% and 96% respectively, based on an average prevalence of 14% in the study population. In a low-prevalence population (5%), the positive predictive value decreases to 31%; the negative predictive value remains at 96%.(Package insert: Platelia Aspergillus EIA, Bio-Rad Laboratories; 06/2003)
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-General Request (T239)