Test Id : GFATS
Glial Fibrillary Acidic Protein Alpha Subunit Antibody, Immunofluorescence Titer Assay, Serum (Non-Orderable)
Useful For
Suggests clinical disorders or settings where the test may be helpful
Only orderable as a reflex. For more information see PNEFS / Neuroimmunology Antibody Follow-up, Serum.
Reporting an end titer result in serum specimens
Distinguishing autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy from infectious meningoencephalitis and idiopathic inflammatory central nervous system disorders, such as multiple sclerosis, vasculitis and sarcoidosis, disorders commonly considered in the differential diagnosis
Alerting the clinician that the patient has an immune-mediated, steroid-responsive disorder and to search for a malignancy
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
If immunofluorescence assay (IFA) pattern suggests glial fibrillary acidic protein (GFAP), then the GFAP IFA titer and GFAP cell-binding assay are performed at an additional charge.
Method Name
A short description of the method used to perform the test
Only orderable as a reflex. For more information see PNEFS / Neuroimmunology Antibody Follow-up, Serum.
Indirect Immunofluorescence Assay (IFA)
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
Meningoencephalitis
Meningoencephalomyelitis
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
If immunofluorescence assay (IFA) pattern suggests glial fibrillary acidic protein (GFAP), then the GFAP IFA titer and GFAP cell-binding assay are performed at an additional charge.
Specimen Type
Describes the specimen type validated for testing
Serum
Necessary Information
Provide the following information:
-Relevant clinical information
-Ordering healthcare professional name, phone number, mailing address, and email address
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Only orderable as a reflex. For more information see PNEFS / Neuroimmunology Antibody Follow-up, Serum.
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 4 mL Serum
Collection Instructions: Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
Serum: 1 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 28 days | |
| Ambient | 72 hours | ||
| Frozen | 28 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Only orderable as a reflex. For more information see PNEFS / Neuroimmunology Antibody Follow-up, Serum.
Reporting an end titer result in serum specimens
Distinguishing autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy from infectious meningoencephalitis and idiopathic inflammatory central nervous system disorders, such as multiple sclerosis, vasculitis and sarcoidosis, disorders commonly considered in the differential diagnosis
Alerting the clinician that the patient has an immune-mediated, steroid-responsive disorder and to search for a malignancy
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
If immunofluorescence assay (IFA) pattern suggests glial fibrillary acidic protein (GFAP), then the GFAP IFA titer and GFAP cell-binding assay are performed at an additional charge.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Glial fibrillary acidic protein (GFAP)-IgG is a biomarker of a subacute, progressive autoimmune meningitis, encephalitis, and myelitis. These disorders may mimic multiple sclerosis or other idiopathic inflammatory central nervous system disorders, such as sarcoidosis. Neurologic manifestations include headache, optic neuropathy, transverse myelitis, cognitive decline, and cerebellar ataxia. Cerebrospinal fluid findings are inflammatory. Cranial magnetic resonance imaging reveals linear perivascular enhancement oriented radially to the ventricles. A paraneoplastic neurologic association is common. Reported neoplasms accompanying neurologic symptoms include adenocarcinomas of the prostate and gastroesophageal tract, myeloma, melanoma, colonic carcinoid, parotid pleomorphic adenoma, and teratoma. If GFAP-IgG is detected by immunofluorescence assay, testing for the alpha isoform of GFAP (GFAPalpha-IgG) by cell-based assay is performed.
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.
Only orderable as a reflex. For more information see PNEFS / Neuroimmunology Antibody Follow-up, Serum.
<1:240
Interpretation
Provides information to assist in interpretation of the test results
Seropositivity for autoantibody (positive) is supportive of autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy, a treatable form of meningoencephalomyelitis. A paraneoplastic basis should be considered, according to age, sex, and other risk factors.
Patients who are GFAP-IgG positive have increased risk of tumor. GFAP-IgG increases the likelihood of certain malignancies being found within 2 years of symptom onset (34%). The most common malignancy found is ovarian teratoma (22%).
Glial fibrillary acidic protein meningoencephalomyelitis is immunotherapy responsive. GFAP-IgG positive patients have better outcomes after treatment with corticosteroids.
The presence of GFAP-IgG alerts the clinician that the patient has an immune-mediated, steroid-responsive disorder and directs patient care accordingly. It also alerts the clinician to search for a malignancy.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Fang B, McKeon A, Hinson SR, et al: Autoimmune glial fibrillary acidic protein astrocytopathy: a novel meningoencephalomyelitis. JAMA Neurol 2016;73(11):1297-1307
2. Flanagan EP, Hinson SR, Lennon VA, et al: Glial fibrillary acidic protein immunoglobulin G as biomarker of autoimmune astrocytopathy: Analysis of 102 patients. Ann Neurol 2017;81(2):298-309
3. Iorio R, Damato V, Evoli A, et al: Clinical and Immunological characteristics of the spectrum of GFAP autoimmunity: a case series of 22 patients. J Neurol Neurosurg Psychiatry 2018;89(2):138-146 doi:10.1136/jnnp-2017-316583
Method Description
Describes how the test is performed and provides a method-specific reference
The patient's specimen is tested by a standardized immunofluorescence assay that uses a composite frozen section of mouse cerebellum, kidney, and gut tissues. After incubation with the specimen and washing, fluorescein-conjugated goat-antihuman IgG is applied. Neuron-specific autoantibodies are identified by their characteristic fluorescence staining patterns. Specimens that are scored positive for any neuronal nuclear or cytoplasmic autoantibody are titrated. Interference by coexisting non-neuron-specific autoantibodies can usually be eliminated by serologic absorption.(Honorat JA, Komorowski L, Josephs KA, et al. IgLON5 antibody: Neurological accompaniments and outcomes in 20 patients. Neurol Neuroimmunol Neuroinflamm. 2017;4[5]:e385. doi:10.1212/NXI.0000000000000385)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Sunday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
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
Indicates the location of the laboratory that performs the test
Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
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 instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
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 Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
86256
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| GFATS | GFAP IFA Titer, S | 93423-2 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| 605133 | GFAP IFA Titer, S | 93423-2 |