If your child is on leucovorin, there is one question worth asking: was the FRAT ever actually run? It changes whether you are treating something real.
In cerebral folate deficiency, antibodies block the folate receptor that moves folate across into the brain. Plenty in the blood, not enough where it is needed.
Cerebral folate deficiency drives OCD, anxiety, irritability, rigidity and developmental regression — the exact symptoms families are already chasing. It is treatable with leucovorin (folinic acid), which can cross into the brain by a different route.
So it is worth ruling in or out rather than guessing.
FRAT — the Folate Receptor Antibody Test. It measures the blocking and binding autoantibodies directly. That is the confirmation; a serum folate level is not.
If your child is already on leucovorin and doing well: wonderful. The response itself is meaningful evidence. Knowing the FRAT result still helps you decide how long to continue.
If your child was started on leucovorin without confirmation and is not clearly better — or has become more irritable — that is worth revisiting with the prescriber. Folate is not neutral; in some children extra folate worsens irritability and OCD-type symptoms.
Never stop or change a prescription on your own. This is a question to bring to whoever prescribed it.
Want this answered for your own child? A Plan B synthesis reads every lab and note you have — together — and tells you what is driving the picture, what has never been checked, and what to ask for next.
The first one is free, and you keep the list either way. Phone photos of labs are fine.
Plan B for PANS is written by a parent, not a physician. Nothing here is medical advice or a substitute for your child's clinicians — it is meant to make you the best-informed person in the room when you talk to them.