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Are Blood Tests Used to Diagnose ADHD? 

PostedOctober 13, 2025
UpdatedOctober 13, 2025
ByMy Patient Advice
Author: Avery Lombardi, MSc | Reviewed by: Dr. Rebecca Fernandez, MBBS

No, blood tests do not diagnose ADHD. ADHD is a neurodevelopmental condition diagnosed through behavioural and psychological evaluation not physical or biological testing. Despite ongoing research into possible biomarkers, there are currently no approved medical tests that can confirm or rule out ADHD based on blood samples. 

Diagnosis relies on clinical observation and structured tools, such as interviews, rating scales, and symptom checklists. These methods help assess whether a person meets the diagnostic criteria for ADHD, based on patterns of inattention, impulsivity, and/or hyperactivity that interfere with daily life.  

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Why Blood Tests Aren’t Used for ADHD Diagnosis 

Following are some reasons why blood tests do not diagnose ADHD: 

No Established Biomarkers  

Research into potential biomarkers for ADHD like specific proteins or hormone levels is still in early stages and has not led to any reliable or validated blood-based test. 

Behaviour-Based Diagnosis  

ADHD is identified through behaviour patterns and functional impairments, not physical symptoms detectable through blood work. 

Use of Medical Tests  

In some cases, doctors may order medical tests to rule out other health conditions that could affect mood, focus, or energy, but these are supportive not diagnostic measures. 

In conclusion, although blood work may be used during a broader health check to rule out other medical conditions (such as thyroid issues or vitamin deficiencies) that could mimic ADHD symptoms, it is not part of the diagnostic criteria itself.  

Visit providers like ADHD Certify for personal consultations and expert guidance tailored to your unique situation. 

For a deeper dive into the science, diagnosis, and full treatment landscape, read our complete guide to Signs, Symptoms, and Self-identification of ADHD.  

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Avery Lombardi, MSc, author for my patient advice - mypatientadvice.co.uk
Avery Lombardi, MSc
Author

Avery Lombardi is a clinical psychologist with a Master’s in Clinical Psychology and a Bachelor’s in Psychology. She has professional experience in psychological assessment, evidence-based therapy, and research, working with both child and adult populations. Avery has provided clinical services in hospital, educational, and community settings, delivering interventions such as CBT, DBT, and tailored treatment plans for conditions including anxiety, depression, and developmental disorders. She has also contributed to research on self-stigma, self-esteem, and medication adherence in psychotic patients, and has created educational content on ADHD, treatment options, and daily coping strategies.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the author's privacy. 

Dr. Rebecca Fernandez, MBBS, author and a reviewer for my patient advice - mypatientadvice.co.uk
Dr. Rebecca Fernandez, MBBS
Reviewer

Dr. Rebecca Fernandez is a UK-trained physician with an MBBS and experience in general surgery, cardiology, internal medicine, gynecology, intensive care, and emergency medicine. She has managed critically ill patients, stabilised acute trauma cases, and provided comprehensive inpatient and outpatient care. In psychiatry, Dr. Fernandez has worked with psychotic, mood, anxiety, and substance use disorders, applying evidence-based approaches such as CBT, ACT, and mindfulness-based therapies. Her skills span patient assessment, treatment planning, and the integration of digital health solutions to support mental well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the reviewer's privacy.