# Recommended Medical Investigations in Pediatric Acute-Onset Neuropsychiatric Syndrome

## TL;DR

A study finds that recommended lab tests for PANS do not reliably distinguish it from OCD/tic disorders or identify underlying health issues in children.

## Contribution

The study is the first to compare PANS lab results with psychiatric controls, challenging the clinical value of current diagnostic protocols.

## Key findings

- Abnormal lab findings were common in both PANS and control groups with no significant differences.
- Most recommended medical investigations failed to identify underlying somatic conditions in PANS children.
- Only two PANS cases had actionable findings (celiac disease and neuroinflammatory signs).

## Abstract

Does the comprehensive set of laboratory investigations recommended for children with pediatric acute-onset neuropsychiatric syndrome (PANS) differentiate them from children with idiopathic obsessive-compulsive disorder (OCD) and/or tic disorders, and do these investigations help identify underlying somatic conditions?

In this case-control study of 51 children with PANS and a control group of 58 children with idiopathic OCD and/or tic disorders, nonspecific abnormal laboratory findings were common in both groups, with no between-group differences. The full set of medical investigations recommended for PANS failed to identify underlying somatic conditions in nearly all children with PANS.

These findings question the clinical utility of the comprehensive medical investigations currently recommended for suspected PANS.

This case-control study evaluates whether recommended laboratory tests for pediatric acute-onset neuropsychiatric syndrome (PANS) differentiate PANS from idiopathic obsessive-compulsive and tic disorders and identify underlying somatic conditions in children with PANS in Sweden.

The clinical utility of the comprehensive laboratory and medical investigations currently recommended for children with pediatric acute-onset neuropsychiatric syndrome (PANS) remains unclear. Notably, comparisons with relevant psychiatric control patients without suspected immunologic pathogenesis are lacking.

To evaluate whether currently recommended laboratory investigations differentiate children with PANS from children with idiopathic obsessive-compulsive disorder (OCD) and/or tic disorders and whether the full set of recommended medical investigations identify underlying somatic conditions in children with PANS.

This case-control study recruited children (aged 4-18 years) with PANS and children with idiopathic OCD and/or tic disorders (control group) from specialist PANS and OCD clinics in Stockholm, Sweden, between January 1, 2020, and September 19, 2023. The data analyses were performed between June 16, 2024, and August 19, 2025.

Following published PANS guidelines, assessments included 56 laboratory variables from blood and throat cultures. Additional data from cerebrospinal fluid analysis, brain magnetic resonance imaging, and electroencephalography were available for a subsample of the PANS group. Laboratory findings were compared between the PANS and control groups.

Among 109 participants, the PANS group included 51 children (mean [SD] age, 10.2 [3.4] years; 34 boys [66.7%], and the control group included 58 children (mean [SD] age, 13.6 [3.1] years; 29 boys [50.0%]). Nearly all participants had at least 1 abnormal laboratory finding (44 [86.3%] in the PANS group, 56 [96.6%] in the control group), with no significant between-group differences. Most participants in the PANS group had 3 or more abnormal laboratory findings, while most in the control group had 4 or more. One participant with PANS was diagnosed with celiac disease; another showed electroencephalographic signs of neuroinflammatory activity without a definite diagnosis prior to the PANS assessment. Incidental, nonactionable findings were frequent.

In this case-control study of children with PANS and idiopathic OCD and/or tic disorders, abnormal laboratory findings were common in both groups and did not differ significantly. The full set of recommended medical investigations rarely identified underlying somatic conditions in children with PANS. These findings question the clinical utility of the comprehensive and costly medical investigations currently recommended for children with suspected PANS.