What blood work is recommended for diagnosing insomnia (sleep disorder)?

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Last updated: May 23, 2025View editorial policy

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From the Guidelines

Blood work for insomnia is not routinely recommended as a first-line diagnostic approach, but rather as a tool to identify potential underlying medical causes of sleep difficulties, as suggested by the VA/DOD CPG 1. When evaluating patients with insomnia, it's essential to consider a comprehensive sleep assessment, including the use of the Insomnia Severity Index or Athens Insomnia Scale, as recommended by the VA/DOD CPG 1. Some key points to consider when ordering blood work for insomnia include:

  • Checking thyroid function (TSH, T3, T4) to rule out thyroid disorders, which can contribute to sleep disturbances 1
  • Complete blood count (CBC) to identify potential anemia or other blood-related disorders that may affect sleep
  • Comprehensive metabolic panel (CMP) to assess glucose and electrolyte levels, which can impact sleep quality
  • Iron studies (ferritin, iron, TIBC) to diagnose iron deficiency, which can lead to restless legs syndrome and disrupt sleep
  • Vitamin D levels, as deficiencies have been linked to sleep disorders
  • Inflammatory markers like C-reactive protein to assess overall inflammation, which can contribute to sleep difficulties It's crucial to note that the VA/DOD CPG does not recommend additional diagnostic testing for patients with chronic insomnia disorder who do not respond to CBT-I or pharmacotherapy 1. Therefore, a targeted approach to blood work, based on individual patient symptoms and medical history, is recommended, rather than routine testing for all patients with insomnia.

From the Research

Blood Work for Insomnia

There is no direct evidence of blood work being a primary diagnostic tool for insomnia. However, some studies suggest that evaluating the symptom of insomnia requires assessing whether an underlying condition explains it 2.

Diagnostic Approach

A meticulous history from the patient, supplemented by collateral history from an observer, is essential to establishing the diagnosis of sleep disorders, including insomnia 3.

Investigation and Diagnosis

Judicious supplementary use of investigations, such as laboratory polysomnography, home sleep apnea testing, wrist actigraphy, and multiple sleep latency tests, can confirm the correct diagnosis of sleep disorders 3.

Treatment Options

Treatment options for insomnia include cognitive behavioral therapy, pharmacologic therapies, and digital therapeutics 4, 5, 6.

Key Considerations

  • Insomnia can be comorbid with psychiatric, medical, and neurologic disorders, and insomnia and comorbid conditions have bidirectional relationships 5.
  • Selection of treatment for patients with insomnia should factor in efficacy for the patient's specific complaint as well as other features such as safety profile and abuse liability 5.
  • A "personomics" approach can be used to personalize care plans for patients with insomnia, considering individual characteristics and needs 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Insomnia.

Annals of internal medicine, 2021

Research

Diagnostic Approach and Investigation in Sleep Medicine.

Continuum (Minneapolis, Minn.), 2017

Research

The assessment and management of insomnia: an update.

World psychiatry : official journal of the World Psychiatric Association (WPA), 2019

Research

Diagnosing and Treating Insomnia in Adults and Older Adults.

The Journal of clinical psychiatry, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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