Do I have the restless legs syndrome (RLS)?
Is there a test for RLS?
There is no blood test, or any other physical test for that matter, to diagnose RLS. A doctor will rely on clinical factors to make a diagnosis. Typically a doctor will order a blood test for ferritin (Iron) levels and to check kidney function, blood sugar (to rule out diabetic neuropathy) and thyroid function. The doctor will ask about medication(s) being taken. For more information, see the description of RLS diagnosis from the Sleep Health Foundation. Your primary care doctor (GP) usually can diagnose and treat RLS. However, they may suggest that you see a sleep specialist or neurologist.
How is RLS diagnosed?
A diagnosis of RLS is made if the following 5 criteria are met:
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A discomfort in the legs that results in an overwhelming urge to move the legs.
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Symptoms worsen when resting such as sitting or lying down.
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Symptoms improve with movement such as walking or stretching.
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Symptoms are worse in the evening or night.
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The symptoms cannot be solely attributed to another medical condition for example leg cramps, positional discomfort or arthritis.
For more information, see the "How do I know if I have RLS" section from the Restless Legs Syndrome Foundation.
RLS diagnosis can be broadly separated into 2 categories of severity being intermittent and chronic persistent RLS.
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Intermittent RLS: Symptoms occurring on average less than twice a week for the past year, with at least five lifetime events.
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Chronic–persistent RLS: Symptoms occurring on average at least twice weekly for the past year.
RLS is also classified based on causal factors as:
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Primary RLS: The RLS is the main condition being genetic or idiopathic (no known cause).
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Secondary RLS; The RLS occurs as a result of another disorder (e.g. peripheral neuropathy).
Did you know that humans are the only mammals that delay sleep. We are the only species that intentionally puts off sleeping for other activities, such as working, socializing, or using technology.
The IRLS symptom rating scale
The International Restless Legs Syndrome Study Group (IRLSSG) Rating Scale (often referred to as the IRLS) is a validated, 10-item questionnaire used to assess the severity and impact of RLS symptoms over the past week. This scale is designed to measure the severity of the RLS in patients who have already been diagnosed based on the 5 standard criteria above. The rating scale is not a diagnostic tool, it is a symptomatic tool, designed to assess disease severity and guide therapeutic outcomes. The patient rates each of the 10 questions on a scale of 0 to 4 being (4) Very severe (3) Severe (2) Moderate (1) Mild (0) None.
After answering all 10 questions, the scores are totaled to produce a score ranging from 0 to 40. Very severe=31-40 points; Severe=21-30 points; Moderate=11-20; points Mild=1-10 points; None=0 points. The IRLS 10 question rating scale can be downloaded in PDF format here.
In some instances a doctor may ask for an overnight sleep test (polysomnography) to see if there are other sleep disorders (e.g. Sleep apnoea) that may be contributing to daytime symptoms.
In some instances when you see a doctor for restless legs syndrome (RLS) they will order a sleep test which is called polysomnography. Quite simply "poly" means many, "somno" means sleep and "graphy" means recordings. So put together polysomnography means "many sleep recordings". In a sleep study typically you have some electrodes on your head (EEG), electrodes on the outside of the eyes (electro-oculogram [EOG]) to measure eye movement (helps detection of REM sleep), a thermistor (temperature probe under your nose (measures air flow - useful in detecting sleep apnoea), belts around the chest and abdomen (measure the action of breathing), sometimes electrodes on the legs (measure leg muscle activation - useful for detecting the periodic limb movement syndrome [PLMS]). Also possible are some electrodes on your chest to measure your heart rhythm (ECG). Lastly there is an oximeter attached to a finger (measures blood oxygen - useful in the detection of sleep apnoea).
Measuring sleepiness: The Epworth Sleepiness Scale (ESS)
During REM (rapid eye movement) sleep, the brain releases chemicals that temporarily paralyze the muscles. This is known as "atonia". This muscle paralysis has evolved to prevent you from physically acting out your dreams and potentially hurting yourself.
Restless Legs Syndrome (RLS) often leads to sleep onset insomnia and/or sleep fragmentation. These disruptions in sleep quality and quantity produce daytime symptoms, one of which is excessive daytime sleepiness. Estimates are that 20–25% of untreated patients with idiopathic RLS are at an increased risk for daytime sleepiness. The Epworth Sleepiness Scale (ESS) is a commonly used, self-administered questionnaire used in the assessment of RLS patients, primarily to evaluate the presence and severity of excessive daytime sleepiness. The ESS is an 8 item questionnaire with the sum of responses being above 10 generally considered indicative of excessive daytime sleepiness. A PDF of the ESS can be downloaded here.
If an RLS patient scores above 10, it may alert the physician to look for co-existing sleep disorders, such as sleep apnoea or periodic limb movement disorder (PLMD), which could be compounding the patient's sleep quality issues. The ESS helps Dr's quantify whether a patient's sleep issues are causing significant daytime impairment. The ESS is used to track changes in a patient's condition in response to therapeutic interventions.
For more information see the Epworth Sleepiness scale - About the ESS website.
Deep sleep (also known as slow-wave sleep is the most restorative phase of the sleep cycle. Deep sleep is when the body and brain perform critical maintenance tasks. During deep sleep the body releases growth hormones that are essential for repairing tissues, building muscle, and healing injuries. This is the period when physical energy stores are replenished. Deep sleep plays a vital role in strengthening the immune system. It is also involved in regulating glucose metabolism and appetite controlling hormones. In deep sleep the brain flushes out metabolic waste products (such as beta-amyloid proteins) that accumulate during waking hours, which is linked to long-term neurological health.
Last reviewed: 03/08/2026