Folate Receptor Autoantibody Test (FRAT)

Beschrijving

The FRAT is a blood test that measures autoantibodies against the folate receptor alpha. These autoantibodies may impair folate transport across the blood-brain barrier and have been associated with cerebral folate deficiency and several neurodevelopmental and neuropsychiatric conditions.

About this test

The Folate Receptor Autoantibody Test (FRAT) is a specialized blood test used to detect folate receptor alpha autoantibodies (FRAAs). According to the official FRAT information, this assay identifies both blocking and binding autoantibodies, which is clinically relevant because these antibodies may interfere with the normal transport of folate into tissues, including transport across the blood-brain barrier.

Folate is essential for neurological development and function, methylation, DNA synthesis, and normal cellular metabolism. When folate receptor autoantibodies are present, folate delivery to the brain and cerebrospinal fluid may be reduced despite apparently adequate folate intake.

When can this test be relevant?

This test may be considered in patients with clinical suspicion of folate receptor autoimmunity or disturbed cerebral folate transport. The official FRAT source reports associations with:

• Cerebral Folate Deficiency Syndrome
• Autism Spectrum Disorder
• Depression
• Schizophrenia
• Other neurodevelopmental and neuropsychiatric disorders

A reasoned clinical view is that the test is most useful when the history suggests neurological, developmental, behavioral, or treatment-resistance features where impaired folate transport could be part of the picture.

What does the test measure?

The FRAT measures:

• Blocking folate receptor autoantibodies
• Binding folate receptor autoantibodies

The official FRAT FAQ also states that results may include titer levels for the specific autoantibody types detected.

Clinical significance

A positive FRAT result suggests the presence of folate receptor autoantibodies that may impair physiological folate transport. The official FRAT materials specifically note possible relevance for brain folate delivery and CSF folate availability.

A negative result suggests that these specific folate receptor autoantibodies were not detected at the time of testing.

Why choose this test?

• Detects both blocking and binding folate receptor autoantibodies.
• Can support work-up in suspected cerebral folate transport disturbance.
• May help guide a more targeted clinical discussion around folate-related mechanisms. This is a clinical inference based on the test’s intended use as described by the official FRAT source.

Important Pre-Test Information

Patients using folinic acid, 5-MTHF, or other active folate-containing supplements are advised to temporarily discontinue these supplements for 48 hours before sample collection. Residual circulating folate metabolites may potentially affect the quantitative measurement of Folate Receptor Autoantibodies (FRAT®).

Please note: This analysis is performed by an external specialized reference laboratory. The expected turnaround time is approximately 6–8 weeks after sample receipt.

Suitable for postal submission.