In-laboratory sleep study

What is an in-laboratory sleep study (polysomnography)?

An in-laboratory sleep study, or polysomnography, is the most detailed sleep test. You spend a night in a sleep unit wearing a range of sensors that record your brain waves, eye and chin movements, breathing through the nose and mouth, the effort your chest and tummy make, your oxygen level, heart rhythm and leg movements.

Because it records brain waves, it can measure your sleep stages and exactly how much you slept, as well as your breathing. This makes it the reference test for obstructive sleep apnoea and the main way to investigate more complex or non-respiratory sleep disorders such as periodic limb movements, unusual night-time behaviours and suspected narcolepsy.

It is more involved than a home study and sleeping in an unfamiliar place with sensors on can itself disturb sleep. It is usually reserved for when a home study has not given a clear answer, when symptoms continue despite a negative home study, or when the problem is likely to be more than simple sleep apnoea.

Types, options & approaches

There may be different ways to do this. The right approach depends on the clinical question and your circumstances.

In-laboratory study vs home sleep study

Most people start with a home study. An in-laboratory study is used when more detail is needed, the home study was negative but symptoms continue, or the problem may be more than sleep apnoea.

Preparing for your test

• You will usually arrive at the sleep unit in the evening; bring nightclothes, toiletries and any usual medicines.
• Wash and dry your hair beforehand and avoid hair products, gel or heavy moisturiser so the scalp and skin sensors stick.
• Avoid caffeine in the afternoon and evening, and avoid alcohol and sedatives unless your clinician advises otherwise.
• Try to keep your usual daytime routine and avoid daytime naps, so you sleep at the unit.
• Bring a list of all your medicines and tell staff about any you take to sleep or for restless legs.
• Mention nasal blockage, home oxygen, or any existing CPAP or breathing device.
• Arrange how you will get home the next morning, as you may be tired and leave early.
• Ask whether you can bring your own pillow or comfort items to help you settle.

What happens

You arrive at the sleep unit in the evening and are shown to a private bedroom. A sleep physiologist attaches sensors: small pads on your scalp and face for brain waves and eye and chin movements, a soft tube and sensors at the nose and mouth for airflow, bands around your chest and tummy for breathing effort, a finger probe for oxygen, ECG dots for heart rhythm and sensors on your legs for movement.

The sensors are connected to a recorder, and staff can monitor the signals and sometimes video through the night from another room. You then sleep as normally as you can. If you need the toilet, staff can briefly disconnect you. It is usually not painful and there are no needles for the recording itself.

In the morning the sensors are removed and you can usually go home. The large amount of data is then scored in detail by a sleep scientist and reviewed by a consultant, who interpret your sleep stages, breathing events and movements alongside your symptoms before producing a report.

Is this test right for me?

A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.

Before you decide

Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.

The main downsides are inconvenience and a possibly untypical night rather than physical danger. Sleeping in a unit with many sensors can change how you sleep, so the result is always read alongside your symptoms. Ask what the plan is if the study is normal but you still feel unwell.

Published figures to discuss

Polysomnography carries no meaningful physical risk; the relevant uncertainties are night-to-night variability, the chance of an untypical or non-diagnostic night needing repeat, and the fact that a single setting may not capture every problem. These vary with the individual, the suspected disorder and how well the person sleeps in the unit, so fixed figures are not meaningful.

These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.

What happens afterwards

There is no physical recovery from polysomnography. After the sensors come off you can go home and resume normal activities, then wait for the detailed recording to be scored and reported.

• Feeling tired the next day after an untypical night's sleep
• Skin marks or redness where sensors were attached, which settle
• Sticky paste in the hair that washes out
• A few weeks' wait while the detailed recording is scored and reported

Aftercare

• Wash your hair to remove any electrode paste once you are home.
• Take it easy if you are tired the next day, especially before driving.
• Note anything that made the night unusual and tell the team, as it helps interpretation.
• Wait for the formal report rather than drawing conclusions from the night itself.
• Keep your follow-up appointment to discuss the result and any treatment.
• If you were tested for sleepiness, take care with driving until advised, and if you are told to notify the driving licence authority, contact the DVLA if you live in England, Scotland or Wales, or the DVA if you live in Northern Ireland.

• Nightclothes, toiletries and usual medicines packed
• Hair washed and product-free for the scalp sensors
• List of medicines, including sleep and restless-leg treatments
• Caffeine, alcohol and daytime naps avoided beforehand
• Transport home arranged for the morning
• A note of who will give the result and when

⚠ Get urgent help if…

• Severe daytime sleepiness, especially falling asleep while driving — stop driving and seek urgent advice
• Choking, gasping or witnessed stopping of breathing in sleep
• New or worsening breathlessness, especially at rest or lying flat
• Chest pain, palpitations or fainting
• Sudden muscle weakness with strong emotion, or sleep paralysis, which should be mentioned promptly
• Blue or grey lips or fingertips — seek urgent medical help

Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.

General guidance — it doesn't replace the specific advice your specialist gives you.

Results & realistic expectations

A good study shows your clinician how you moved through sleep stages, how often your breathing paused or became shallow, how your oxygen and heart rhythm behaved and whether your legs moved abnormally. Together these can confirm obstructive sleep apnoea and its severity, or point to another sleep disorder.

Even this detailed test reflects one night and a single setting, so a normal result does not guarantee perfect sleep on every night or exclude every problem. The findings are interpreted alongside your symptoms, and sometimes a repeat or a daytime test is needed.

A study reflects the night recorded. If your weight, symptoms, medicines or general health change, the result may no longer apply and repeat testing may be needed. After starting treatment, a further study is sometimes done to check it is working.

Related tests, treatments or support

Polysomnography is sometimes combined with a CPAP titration in the same night (a split-night study) or followed by daytime nap tests if excessive sleepiness or narcolepsy is suspected. It is also interpreted alongside questionnaires and an assessment of your weight, blood pressure and general health.

Follow-up & long-term care

Your sleep service tells you when the detailed report will be ready and who will explain it. If a disorder is confirmed, you may be offered treatment such as CPAP, a mandibular advancement device or medication, with planned review. If the study is normal but symptoms continue, ask about further assessment.

Repeat, follow-on and what comes next

• A minority of studies are untypical or non-diagnostic and occasionally need repeating.
• A normal study with ongoing symptoms may lead to further or daytime testing.
• After treatment is started, a repeat study is sometimes done to confirm it is working.

Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.

What good aftercare looks like

• A clear report explained by a clinician, set against your symptoms.
• A named contact and a defined next step if the study is normal but you remain symptomatic.
• A plan for treatment, titration or further testing where a disorder is confirmed.
• Safety advice on driving and sleepiness while results are awaited.

What affects the cost

Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:

• Whether it is a diagnostic study, a CPAP titration, a split-night or a daytime test
• The overnight stay in the sleep unit with attending staff
• Detailed scoring of the recording by a sleep scientist
• Consultant review and reporting
• Whether a follow-up consultation to explain the result is included
• Whether further or repeat studies are likely

• The cost of the overnight study and attending staff
• Whether detailed scoring and consultant reporting are included
• Whether a consultation to explain the result is included
• What happens, and what it costs, if the study must be repeated
• Whether any CPAP titration or daytime tests are quoted separately
• The cancellation and rebooking policy

On the NHS? In-laboratory polysomnography is available on the NHS when clinically needed, usually after a home study or for complex sleep problems; private studies are mainly used for speed or choice.

You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.

Consent traps and marketing red flags

These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.

Choosing a specialist safely

• Check the specialist is on the GMC Specialist Register for this area.
• Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
• You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
• Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
• You're entitled to your total cost in writing — including any follow-up — before you decide.

How Vuemedics verifies every consultant →

Take this to your consultation. A good specialist will welcome every one of these.

• Why do I need an in-laboratory study rather than a home study?
• What conditions are you looking for beyond sleep apnoea?
• Will this be a diagnostic study, a CPAP titration, or both in one night?
• What will the result change about my treatment?
• What happens if the study is normal but I still feel unwell?
• Who will explain my report, and when can I expect it?
• Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
• Will you be the specialist who carries out my test, and who looks after me afterwards?
• What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
• What does a realistic result look like — and what can this test not achieve?
• What are my options, including waiting, doing nothing for now, or choosing a different approach?
• Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
• What is the total cost in writing, including any follow-ups, and how much time do I have to decide?

Find a verified specialist for in-laboratory sleep study

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How we made this page

Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →

Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.

Sources & standards: NICE NG202 — OSAHS in over 16s (diagnostic testing) NHS — Sleep apnoea Sleep Apnoea Trust — Diagnosis of sleep apnoea British Thoracic Society — Sleep apnoea resources Clinical and polysomnographic characteristics in sleep-lab adults — PMC Body position differences between lab PSG and home testing — PMC DVLA — Assessing fitness to drive DVA Northern Ireland — Telling DVA about a medical condition

Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.

Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.