NMDA-Receptor Antibody by CBA, Serum
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Evaluating new onset encephalopathy (noninfectious or metabolic) comprising 1 or more of the following: confusional states, psychosis, delirium, memory loss, hallucinations, movement disorders, seizures, or hypoventilation
Evaluating limbic encephalitis
Directing a focused search for cancer
Investigating encephalopathy appearing in the course or wake of cancer therapy, and not explainable by metastasis or drug effect
Cell-binding assay (CBA) detects IgG specific for NMDA-R (N-Methyl-D-aspartate receptor) by indirect immunofluorescence (IFA)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
NMDA-R Ab CBA, Serum
N-Methyl D-Aspartate Ab
NMDA Receptor Ab
N-Methyl D-Aspartate Ab
NMDA Receptor Ab
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.
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 1 mL
Additional Information: Include relevant clinical information, name, phone number, mailing address, and E-mail address (if applicable) of ordering physician
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.
Mild OK; Gross reject
Mild OK; Gross reject
Mild reject; Gross reject
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Serum||Refrigerated (preferred)||28 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Patients with NMDA-receptor antibody (targeting the GluN1 [NR1] subunit of this ionotropic glutamate receptor) have a fairly stereotyped neurological disorder, as described by Dalmau and colleagues. This disorder often develops in several stages. Prodromal symptoms include headache, fever, nausea, vomiting, diarrhea, or upper respiratory tract symptoms. Shortly afterwards, patients develop psychiatric symptoms and many initially come to the attention of psychiatrists. Anxiety, insomnia, fear, delusions, mania, and paranoia frequently occur; drug-induced psychosis may be suspected. Other behavioral changes include social withdrawal and stereotyped behavior. Amnesia and an unusual language disorder (noncortical aphasia) are common. The behavioral changes in children may be less specific and include temper tantrums and hyperactivity. Neurological disorders including seizures and dystonia are frequent, and may be the presenting symptom. After these initial symptoms, in both adults and children, decreased responsiveness ensues. Movement disorders include oro-lingual-facial dyskinesias, generalized chorea, oculogyric crisis, dystonia, and rigidity. Autonomic manifestations include hyperthermia, tachycardia, hypersalivation, hypertension, bradycardia, hypotension, urinary incontinence, and erectile dysfunction. Hypoventilation may necessitate extended ventilatory support (often months). Dissociative responses similar to those caused by NMDA-receptor antagonists (eg, phencyclidine or ketamine) have been observed (eg, resisting eye opening despite lack of response to painful stimuli).
The female:male ratio of patients is about 8:1. Overall, ovarian teratoma is encountered in approximately 50% of affected women. The most useful screening tests include magnetic resonance imaging (MRI) of pelvis, computed tomography (CT) scan, and pelvic and transvaginal ultrasound. The detection of teratoma is dependent on age and ethnic background; the younger the patient, the less likely that teratoma will be detected; black women are more likely to have teratoma than other ethnic groups. Only 2% have a neoplasm other than ovarian teratoma. Neoplasms documented in women include breast adenocarcinoma, ovarian neuroendocrine tumors, sex cord stromal tumor, pseudopapillary neoplasm of pancreas, neuroblastoma, and Hodgkin lymphoma. Neoplasia has been documented in 5% of men: testicular germ cell tumors or small-cell lung carcinoma.
Simultaneous testing of serum and cerebrospinal fluid (CSF) is recommended, because CSF is often more informative for NMDA-receptor antibody.
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.
This is a valuable serological marker of autoimmune encephalopathy and of a patient's immune response to cancer (usually teratoma). NMDA-receptor autoantibodies are usually accompanied by subacute neurological symptoms and signs, and not found in healthy subjects.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
A negative result does not exclude autoimmune encephalopathy or cancer.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Dalmau J, Lancaster E, Martinez-Hernandez E, et al: Clinical experience and laboratory investigations in patients with anti-NMDAR encephalitis. Lancet Neurol 2011;10:63-74
Method Description Describes how the test is performed and provides a method-specific reference
Patient serum is applied to a composite slide containing transfected HEK293 cells. After incubation and washing, fluorescein-conjugated goat IgG reactive with human IgG is applied to detect bound patient IgG.(Lennon VA, Kryzer TJ, Pittock SJ, et al: IgG marker of optic-spinal multiple sclerosis binds to the aquaporin-4 water channel. J Exp Med 2005;202:473-477)
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.
Wednesday, Friday; 8 a.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.
Negative: 2-4 days; Positive: 5-7 days
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.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. 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 Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
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|
|61516||NMDA-R Ab CBA, Serum||In Process|