Ordering Recommendation

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

Mnemonic

NMDA IGG

Methodology

Semi-Quantitative Indirect Fluorescent Antibody

Performed

Sun-Sat

Reported

1-3 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation
Collect

Serum separator tube.

Specimen Preparation

Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.15 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

CSF or plasma. Contaminated, hemolyzed, or severely lipemic specimens.

Remarks
Stability

After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)

Reference Interval

< 1:10

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 test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)

Note

If NMDA antibody IgG is positive, then an NMDA antibody IgG titer is reported. Additional charges apply.

Hotline History

N/A

CPT Codes

86255; if reflexed, add 86256

Components

Component Test Code* Component Chart Name LOINC
2004222 N-methyl-D-Aspartate Receptor Ab, Serum 80221-5
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • Anti-GluN1
  • Anti-NMDA
  • Anti-NR1
  • Glutamate Receptor Antibodies
  • N-Methyl D-Aspartate Ab
  • NMDA R
  • NMDA Receptor Ab
  • NMDA Reflex
  • NMDA Titer
N-methyl-D-Aspartate Receptor Antibody, IgG, Serum with Reflex to Titer