DIAGNOSTIC TEST 875

NMDA Receptor Antibodies (IgG)

Diagnostic test for antibodies against NMDA-R. For suspicion of autoimmune encephalitis.

Indication

Suspicion of anti-NMDA receptor encephalitis or for differential diagnosis of autoimmune encephalitis

Sample material

Serum

  • Minim. volume: 0,5 mL

CSF

  • Minim. volume: 0,5 mL

Transport

Within Sweden

  • room temperature

International

  • cold

Method

Cell-based assay (CBA), Indirect immunofluorescence (IIF)

Reference interval

Serum

  • <1:10 negative

CSF

  • negative

Result

Results are reported as negative or positive. A positive result is followed by a titer (serum).

Interpretation

Antibodies against the NMDAR (NR1 unit) are indicative of autoimmune encephalitis. NMDAR belongs to the family of ionotropic glutamate receptors and is widely expressed in the temporal lobe (limbic system). Signaling initiated by glutamate binding to the NMDA receptor is important for synaptic plasticity and cognitive functions such as memory and learning. Subacute personality change with cognitive effects, hallucinations, epileptic seizures, bizarre behavior, impaired memory, and impaired orientation are examples of symptoms that indicate suspicion of autoimmune encephalitis if infectious cause can be excluded. Autoimmune encephalitis may be associated with malignancy.

NMDAR encephalitis often affects young women but may occur at all ages and in both men and women. NMDAR antibodies can be associated with ovarian teratoma (or testis teratoma for men), reported frequency varies between 9-56%. To avoid tissue damage, early diagnosis and treatment is important. Antibody titers can be used to monitor treatment effectiveness.

Antibodies against NMDA receptor are graded as Intermediate-risk antibodies with a frequency of 38% of underlying cancer and a positive result yield 2 points PNS score, according to Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.

References

  • Leypoldt F et al. Ann N Y Acad Sci. 2015. Autoimmune encephalopathies. PMID: 25315420
  • Dalmau J et al. Physiol Rev. 2017. Autoantibodies to Synaptic Receptors and Neuronal Cell Surface Proteins in Autoimmune Diseases of the Central Nervous System. PMID: 28298428
  • Dalmau J et al. Lancet Neurol. 2019. An update on anti-NMDA receptor encephalitis for neurologists and psychiatrists: mechanisms and models. PMID: 31326280
  • Graus F et al. Neurol Neuroimmunol Neuroinflamm. 2021. Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes. PMID: 34006622
  • Flanagan EP et al. JAMA Neurol. 2023. Autoimmune Encephalitis Misdiagnosis in Adults. PMID: 36441519

Included in these panels

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How to order

This test is available worldwide for hospitals, clinics, and physicians.

  1. Print and complete the request form

    Download the request form. Clearly state the name and phone number of the referring hospital, clinic, or physician.

  2. Prepare your samples

    Serum: At least 0.5 mL serum (plain serum tubes without additives).
    CSF: At least 0.5 mL CSF (polypropylene tubes).

  3. Send samples and request form

    Within Sweden
    Samples can be sent at room temperature to:
    Envelopes and smaller boxes:
    Wieslab AB, Box 50117, 20211 Malmö, Sweden

    Larger boxes and frozen samples:
    Wieslab AB, Lundavägen 151, 21224 Malmö, Sweden

    International
    Send samples cold to:
    Wieslab AB, Lundavägen 151, 21224 Malmö, Sweden

Read our sampling instructions for more information

Last updated: 2025-08-18