What a functional workup for ADHD actually looks at

You already have the diagnosis, or you are close to it. What you do not have is an answer to the question sitting underneath it. Why is it this hard for my kid, and is any part of it something we can change at the body level.

That question is what a functional workup is built for. Here is exactly what one looks at, and exactly where it stops.

What do parents ask me most about this?

Short answers first. The full reasoning is below.

What does a functional workup for ADHD actually test?

A functional workup for ADHD looks at five things. Ferritin and iron studies. 25-OH vitamin D. Zinc and copper, read as a ratio.

Why is ferritin the first lab I look at?

Ferritin measures stored iron, and it is the lab most often missed in a child with attention struggles.

Why check 25-OH vitamin D in a child with attention struggles?

25-OH vitamin D is the marker of vitamin D status. I check it because vitamin D acts on the developing brain, not only on bone.

Why measure zinc and copper as a ratio instead of one at a time?

Zinc and copper compete with each other for absorption and transport. So a single value can look fine while the balance between the two has drifted.

Why run a thyroid panel for an attention problem?

Thyroid hormone sets the pace of the whole system, including activity level and the ability to hold focus.

What does the Organic Acids Test show that blood work does not?

The Organic Acids Test is a urine test I order from Mosaic Diagnostics. It reads the leftovers of metabolism rather than the level of something in blood.

What will a functional ADHD workup not do?

A functional workup will not diagnose ADHD. It will not replace the school evaluation or the developmental pediatrician.

Which tests would I start with?

For most families I start with the Tiny Health PRO gut test plus the Organic Acids Test. Then I run ferritin and iron studies, 25-OH vitamin D, zinc and copper, and a thyroid panel…

What does a functional workup for ADHD actually test?

A functional workup for ADHD looks at five things. Ferritin and iron studies. 25-OH vitamin D. Zinc and copper, read as a ratio. A full thyroid panel. And an Organic Acids Test, which covers neurotransmitter, mitochondrial and yeast patterns. None of those five diagnose ADHD. They look for body-level loads that make attention harder to hold.

Let me be clear about the line I am not crossing. ADHD is a clinical diagnosis, made from history and behavior across settings by a qualified clinician. There is no blood test for it. There is no urine test for it either. Nothing on this list can create the diagnosis or take it away. I do not order labs to replace that process, and I would be skeptical of anyone who says they can.

What a functional workup for ADHD can tell me is something else. It shows whether a child is running attention on empty iron stores. Or low vitamin D. Or an off thyroid. Or a mineral balance that has slipped. Those aren't small things, and they are exactly what goes unchecked when everyone is focused on behavior.

Why is ferritin the first lab I look at?

Ferritin measures stored iron, and it is the lab most often missed in a child with attention struggles. A child can have a normal blood count and still have low stores. The body protects circulating iron first and spends the reserve quietly. Iron is also needed to build dopamine, and dopamine is the chemistry attention runs on.

The research on ferritin and ADHD is consistent. One study compared 53 children with ADHD to 27 controls. Average serum ferritin was 23 ng/mL in the ADHD group and 44 ng/mL in the controls. Ferritin sat below 30 ng/mL in 84% of the children with ADHD, against 18% of controls. Lower ferritin also tracked with more severe rated symptoms.1

A later review pooled 17 studies. It found serum ferritin significantly lower in children with ADHD. Symptoms were more severe in the children who were iron deficient. The odds ratio for the link between ADHD and iron deficiency was 1.64.2

Here is the honest boundary on ferritin. Low iron stores do not cause ADHD, and correcting iron is not a therapy for ADHD. Checking ferritin removes one load from a system that is already working hard. In practice, the children I see with truly low stores are often the same children whose sleep is restless. That overlap is worth reading about alongside natural sleep remedies for kids.

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Why check 25-OH vitamin D in a child with attention struggles?

25-OH vitamin D is the marker of vitamin D status. I check it because vitamin D acts on the developing brain, not only on bone. It is also the low result I find most often in Omaha. A child here can go from October to April without real sun on skin, and nobody thinks to look.

One review pooled 13 observational studies. Children with ADHD had lower serum 25-OH vitamin D than healthy children, by a weighted mean difference of about 6.75 ng/mL. Lower vitamin D status came with roughly two and a half times the likelihood of ADHD.3 The same authors then wrote that the effect sizes are small and the link should be treated as equivocal for now.3 I include their caution because it is theirs, and because it is right.

So I check 25-OH vitamin D for a plain reason. It is cheap and it is ordinary. A low result is worth knowing about in any child, whatever it does or does not have to do with attention.

Why measure zinc and copper as a ratio instead of one at a time?

Zinc and copper compete with each other for absorption and transport. So a single value can look fine while the balance between the two has drifted. I read zinc and copper as a ratio for that reason. The relationship between them carries information that neither number carries alone.

One study compared 58 children with ADHD to 50 healthy children aged 6 to 14. Plasma zinc was lower in the ADHD group and the copper to zinc ratio was higher. Zinc levels tracked with parent-rated and teacher-rated inattention scores. The copper to zinc ratio tracked with teacher-rated inattention.4

And then the limit, stated plainly. A 2023 review of nutrition research in ADHD reached a clear conclusion. Current evidence does not support recommending micronutrient supplements for ADHD.5 I agree with that. Measuring a mineral balance in one child is one thing. Recommending minerals to every child with a diagnosis is another. Only the first one is what I do.

Why run a thyroid panel for an attention problem?

Thyroid hormone sets the pace of the whole system, including activity level and the ability to hold focus. A full thyroid panel is ordinary, inexpensive and occasionally explains something large. I run one because the cost of checking is small and the cost of missing it is not.

The clearest signal in the literature comes from a rare inherited condition. Researchers studied 18 families with generalized resistance to thyroid hormone. Among the children, 70% of those affected met criteria for ADHD. Only 20% of the unaffected children in the same families did, and the pattern held among the adults too.6

That condition is rare. Most children with attention struggles have entirely normal thyroid function. So this is not an argument for screening every child. It is a demonstration that thyroid signaling and attention are wired together.

What does the Organic Acids Test show that blood work does not?

The Organic Acids Test is a urine test I order from Mosaic Diagnostics. It reads the leftovers of metabolism rather than the level of something in blood. Organic acid chromatography can identify several hundred compounds, and quantify the main ones, from a single sample.7 For a child, the best part is that it needs no blood draw.

I use the Organic Acids Test for four things. OAT neurotransmitter markers, which relate to regulation. OAT mitochondrial markers, for energy production. Broader metabolic patterns. And hints of possible mold or yeast overgrowth. Urinary organic acids are an established part of metabolic and mitochondrial evaluation. No single marker is enough on its own there, so clinicians read a combined signature instead.8

The neurotransmitter markers are the part parents ask about most, so here is how I actually read them. A common finding is that a child's brain can make its chemical messengers just fine. Production is not the problem. The trouble looks like transport and use. That single distinction changes what I support and what order I support it in.

Now the limit, because it matters. Urine is not the brain. Those markers give me a pattern to follow. They are not a picture of what is happening inside your child's head. I will not pretend otherwise to make a report look better than it is.

What will a functional ADHD workup not do?

A functional workup will not diagnose ADHD. It will not replace the school evaluation or the developmental pediatrician. It will not decide anything about medication. Those conversations belong with your child's prescriber and primary care provider. I stay in my lane on that deliberately, and I say so out loud in a visit.

A functional workup is also not therapy for a diagnosis. I want that in writing rather than implied. What it does is find the loads making an already hard thing harder. Then a plan gets built on what your child's body is doing, not on a label.

I do not want to treat your child like a diagnosis. ADHD, autism traits, sleep issues, headaches and behavior are all clues, but they do not always tell us why a body and brain are struggling. For the support side of that, natural ADHD support for children and evidence-based natural remedies for ADHD both go further than this post does.

Which tests would I start with?

For most families I start with the Tiny Health PRO gut test plus the Organic Acids Test. Then I run ferritin and iron studies, 25-OH vitamin D, zinc and copper, and a thyroid panel through conventional blood work. That first pairing gives the broadest starting picture for the money, and stool and urine mean no needle on day one.

For a 4-year-old I am thoughtful about whether we truly need the blood draw right away. Sometimes the answer is yes and we do it. Often the stool and urine answer enough of the question that the draw can wait a few months. For a small child, that trade is worth making. Choosing the order of testing, instead of ordering everything at once, is a large part of what a natural pediatrician does. The gut half of it is covered in pediatric gut and microbiome testing.

Sleep gets ruled out along the way, every time. A child who snores every night and moves all night is a child whose attention deserves a sleep answer before anything else gets blamed.

You are not looking for a lab result. You are looking for a reason, and for something you can actually do with it on Monday morning. A workup like this gives you a real map instead of guesswork. It will not explain everything, and I will tell you plainly where it runs out. What it does is turn a pile of behaviors into a short list of things that can be checked. Your child gets to be a whole kid in the middle of it, not a diagnosis.

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Written by Dr. Amy Patton, Founder Happy Kid Functional Medicine

About the author

This article was written by Dr. Amy Patton, DNP, APRN, CPNP-PC, FMACP, a board-certified pediatric nurse practitioner and functional medicine provider serving Omaha-area families through Happy Kid Functional Medicine. Dr. Patton specializes in root-cause pediatric care for children's gut health, sleep, behavior, nutrition, immune patterns, and whole-child wellness. She sees patients in person in Omaha and by telehealth across Arizona, Colorado, Iowa, Nebraska, Tennessee, and Virginia.

References

1. Konofal E, Lecendreux M, Arnulf I, Mouren MC. Iron deficiency in children with attention-deficit/hyperactivity disorder. Arch Pediatr Adolesc Med. 2004;158(12):1113–1115. PubMed

2. Tseng PT, Cheng YS, Yen CF, et al. Peripheral iron levels in children with attention-deficit hyperactivity disorder: a systematic review and meta-analysis. Sci Rep. 2018;8(1):788. PubMed

3. Khoshbakht Y, Bidaki R, Salehi-Abargouei A. Vitamin D status and attention deficit hyperactivity disorder: a systematic review and meta-analysis of observational studies. Adv Nutr. 2018;9(1):9–20. PubMed

4. Viktorinova A, Ursinyova M, Trebaticka J, et al. Changed plasma levels of zinc and copper to zinc ratio and their possible associations with parent- and teacher-rated symptoms in children with attention-deficit hyperactivity disorder. Biol Trace Elem Res. 2016;169(1):1–7. PubMed

5. Lange KW, Lange KM, Nakamura Y, Reissmann A. Nutrition in the management of ADHD: a review of recent research. Curr Nutr Rep. 2023;12(3):383–394. PubMed

6. Hauser P, Zametkin AJ, Martinez P, et al. Attention deficit-hyperactivity disorder in people with generalized resistance to thyroid hormone. N Engl J Med. 1993;328(14):997–1001. PubMed

7. Van Noolen L, Acquaviva-Bourdain C, Dessein AF, et al. Recommendations for urinary organic acids analysis. Ann Biol Clin (Paris). 2020;78(5):547–554. PubMed

8. Boenzi S, Diodato D. Biomarkers for mitochondrial energy metabolism diseases. Essays Biochem. 2018;62(3):443–454. PubMed

Medical disclaimer: This article is educational and is not medical advice. It does not diagnose, treat, or replace individualized care from your child's pediatrician or licensed medical provider. Supplement types, doses, and combinations should be selected with a qualified clinician who knows your child's full history — never start a new supplement based on a blog post alone. Always consult your pediatrician before making changes to your child's routine, and seek prompt medical care for snoring with gasping or pauses in breathing during sleep, or for any severe, sudden, or concerning symptom.

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.