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 NMDAR (NR1 unit) suggest autoimmune encephalitis.

NMDAR is a glutamate receptor that is abundantly expressed in the temporal lobe (limbic system). Cognitive impact with subacute personality changes, hallucinations, bizarre behaviour, impaired memory and orientation as well as epileptic seizures are typical symptoms that raise suspicion of encephalitis.

NMDAR encephalitis often affects young women, but can occur in any age and can also affect men. Antibodies against NMDAR can be associated with teratomas (ovary or testis), with reported frequency ranging between 9-56%. Antibody titers can be used to monitor treatment efficacy.

Antibodies against NMDAR can also occur after herpes encephalitis, symptoms present within 1-3 months. This post-infectious autoimmunity can be misinterpreted as a recurrence of the infection.

Antibodies against NMDA receptor are graded as Intermediate-risk antibodies of underlying cancer and gives 2 points PNS score, according to Updated Diagnostic Criteria for Paraneoplastic Neurologic Syndromes.

References

  • 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
  • Kerstens J et al. Neurol Neuroimmunol Neuroinflamm. 2024. Autoimmune Encephalitis and Paraneoplastic Neurologic Syndromes: A Nationwide Study on Epidemiology and Antibody Testing Performance. PMID: 39467237
  • de Bruijn MAAM et al. Nat Rev Dis Primers. 2025. Autoimmune encephalitis. PMID: 40935848
  • Cleaver J et al. J Infect. 2025. Clinical phenotype and outcomes in autoimmune encephalitis after herpes simplex virus encephalitis: A systematic review and meta-analysis. PMID: 40780589

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. If you are a new customer, please also include a completed customer information form.

  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

Last updated: 2026-09-21