Laboratory Test Guide

NMDA Receptor IgG Antibody with Reflex, CSF (Sendout)

General Information

Lab Name

NMDA Receptor IgG Antibody w/Reflex, CSF (Sendout)

Lab Code

RCNMDA

Epic Name

NMDA Receptor IgG Antibody w/Reflex, CSF (Sendout)

External Test Id

2005164

Description

Ordering Recommendation: Confirm diagnosis of anti-NMDAR encephalitis. May be used in monitoring treatment response in individuals who are antibody positive.

Test Algorithm: If NMDA CSF Antibody IgG is positive, then the NMDA CSF Antibody IgG Titer is performed at additional charge.

Ordering Note: Order this test for CSF samples only. For NMDA-R Antibody testing on serum, refer to NMDA Receptor IgG Antibody with Reflex, Serum (Sendout) [RNMDAG].

Synonyms

2005164, Anti NMDA, anti-GluN1, Anti-NMDA CSF, Anti-NR1, Autoimmune Encephalopathy, Glutamate Receptor Antibodies, Limbic encephalitis, N-methyl-D-aspartate receptor, NMDA-R Antibody, Paraneoplastic

Components

Code	Name
RCNMDR	NMDA Receptor IgG Antibody, CSF

Interpretation

Method

Semi-Quantitative Cell-Based Indirect Fluorescent Antibody

Reference Range

See individual components

Ref. Range Notes

Reference Interval:

<1:1

Interpretive Data: Anti-NMDA receptor IgG antibody is found in a subset of patients with autoimmune limbic encephalitis and may occur with or without associated tumor. Decreasing antibody levels may be associated with therapeutic response; therefore, clinical correlation must be strongly considered. A negative test result does not rule out a diagnosis of autoimmune limbic encephalitis.

This indirect fluorescent antibody assay utilizes full-length GluN1 transfected cell lines for the detection and semiquantification of NMDA receptor IgG antibody.

Guidelines

Autoimmune Encephalitis Testing Recommendations

Ordering & Collection

Specimen Type

CSF

Collection

Collect 0.5 mL spinal fluid.

Handling Instructions

Outside Laboratories: Transfer 0.5 mL CSF (min 0.15 mL) to a separate aliquot. Store and transport CSF sample refrigerated.

Stability: Refrigerated (preferred): 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles); Ambient: 48 hours.

Unacceptable Conditions: Contaminated, hemolyzed, or severely lipemic specimens.

Quantity

requested: 0.5 mL CSF
minimum: 0.2 mL CSF

Processing

Transfer 0.5 mL CSF (min 0.15 mL) to a separate aliquot. Refrigerate CSF.

Sendouts:

Order ARUP Test: 2005164
Interfaced: Yes [Interface: 602; Department: ARPR]