Laboratory Test Guide

NMDA Receptor IgG Antibody with Reflex, Serum (Sendout)

General Information

Lab Name

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

Lab Code

RNMDA

Epic Name

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

External Test Id

2004221

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 the NMDA antibody IgG is positive, the NMDA antibody titer will be performed at additional charge.

Ordering Note: This is a non-orderable battery included in package NMDA Receptor IgG Antibody with Reflex, Serum (Sendout) [RNMDAG].

Synonyms

2004221, Anti NMDA, Anti-GluN1, Anti-NR1, Glutamate Receptor Antibodies, Limbic Encephalitis, N-methyl-D-aspartate receptor, NMDA R, Paraneoplastic

Components

Code	Name
RNMDAR	NMDA Receptor IgG Antibody, Serum

Interpretation

Method

Semi-Quantitative Cell-Based Indirect Fluorescent Antibody

Reference Range

See individual components

Ref. Range Notes

Reference Range:

< 1:10

Interpretive Data: NMDA receptor 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. In addition, positive results have been reported in patients with nonautoimmune phenotypes. A negative test result does not rule out a diagnosis of autoimmune limbic encephalitis. Results should be interpreted in correlation with the patients clinical history and other laboratory findings. Serum testing should be paired with CSF testing for improved diagnostic sensitivity.

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

Ordering & Collection

Specimen Type

Blood

Collection

6 mL blood in RED TOP tube or GOLD SST

Quantity

requested: 1 mL serum + 1 mL serum for UW424
minimum: 0.5 mL serum

Processing

Centrifuge sample and transfer 1 mL serum each into two separate plastic vials within 2 hours of collection. If sample volume is low, prioritize the sendout test (RNMDA).

UW424: Freeze serum at -20°C in Immunology rack.
RNMDA: Store serum in Sendouts Refrigerated ARUP rack.

Sendouts:

Order ARUP Test: 2004221
Interfaced: Yes [Interface: 602; Deparment: ARPR]

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

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

Performance

LIS Dept Code

Sendouts ARUP Lab (RF) (ARPR)

Performing Location(s)

Sendout	ARUP Laboratories, Inc. 800-522-2787 500 Chipeta Way Salt Lake City, UT 84108

Frequency

Performed: Sunday through Saturday. Reported: 1-3 days from sample receipt at the performing laboratory.