Autoimmune Encephalitis Tests Miss the Mark 72% of the Time
With the increasing use of commercial autoimmune encephalitis autoantibody test kits, a recent study found a high number of false-positive results leading to misdiagnoses and improper treatment.
While autoantibody tests are informative, considering the tests alone without other clinical context can lead to false positive results.
The clinical criteria for diagnosis autoimmune encephalitis published in 2016 include:
- Rapid onset of short-term memory loss, altered mental state, or psychiatric symptoms
- One or more of the following: unexplained seizures, new problems with nerve, spinal cord, or brain functions that affect a specific part of the body, increased number of white blood cells in the cerebrospinal fluid, or MRI features indicating encephalitis
- Exclusion of other causes
This study examined hospital records and identified 67 patients that had a positive autoimmune encephalitis autoantibody panel result.
However, only 19 of these patients (28%) met the criteria for autoimmune encephalitis as described above, making the false positive rate 72%.
Of those within the false positive group, the most common clinical diagnoses were epilepsy, primary psychiatric disorders, and dementia.
These results highlight the risk of relying on test results alone without also looking at the person’s symptoms, medical history, and other clues. But in reality, many people can’t access a specialist without some form of “confirmed results”.
No diagnosis without a specialist. No specialist without a test result. That’s the autoimmune catch-22.
The study doesn’t address this, but it’s a common experience for those navigating unclear symptoms or suspected autoimmune conditions.
Citation
Al-Qassabi, A., et al. (2025). Clinical and Autoimmune Profiles of Omani Patients with True Versus False Positive Autoimmune Encephalitis Antibodies Panels. Sultan Qaboos University medical journal, 25(1), 242–250. https://doi.org/10.18295/squmj.7.2024.046