What is capillaroscopy?

A painless, non-invasive test that uses a microscope to look at the tiny blood vessels at the base of your fingernails. Doctors study the images to see whether the vessels look normal or show changes.

Discover the test Here for medical training?

Non-invasive
Painless
No needles or X-rays

Reviewed by Borja del Carmelo Gracia Tello

Simplified drawing of a capillaroscope examining a finger near the cuticle, with enlarged capillary loops illustrated on a laptop screen — **At your fingertip**The microscope looks through the skin.
**On the screen**The tiny vessels become visible.
Simplified illustration · not to scale

01 / The microscope

A small microscope with a very close view.

A capillaroscope is a microscope for looking at tiny blood vessels through the skin. A light illuminates the nailfold and a lens magnifies the view.

When it includes a camera, it is called a videocapillaroscope. The images appear on a screen and can be saved for the doctor to study.

It stays outside the skin. Nothing is inserted into your finger.

See what the microscope shows

Simplified drawing of a hand holding a compact capillaroscope, with its lens and focusing ring visible — Illustration of a handheld videocapillaroscope. Other models can be used on a stand.

02 / The images

What does the microscope show?

The small red loops in this image are capillaries. The doctor studies their shape, size and distribution to assess whether they look normal or show changes.

Real nailfold capillaroscopy showing a row of small, looping blood vessels — A normal capillaroscopy example: the small red loops are blood vessels, seen through the skin.

Three things doctors look for

A closer look at the same tiny vessels, from three different perspectives.

Shape

What do the loops look like?

Many normal capillaries look like slender hairpins. The clinician examines their outline and looks for unusual shapes across the images.

Size

How wide are the limbs and apex?

The clinician examines the width of each limb and the apex — the curved tip of the loop. These can have different widths, as the illustration shows.

Distribution

How are they spaced?

The clinician checks how many capillaries are present along the nailfold and how evenly they are arranged, including whether there are gaps.

Simplified illustrations, not measurement scales. Normal vessels vary: the overall pattern across several fingers matters more than one unusual loop.

What does a normal or changed image mean?

A normal finding
Can be reassuring, but does not rule out every condition. Your symptoms and other results still matter.
A change in the vessels
Does not automatically mean disease. Minor injury and normal variation can affect the appearance.
A pattern needing attention
May guide further assessment or follow-up. Your doctor explains what it means in your situation.

Capillaroscopy cannot provide a diagnosis on its own. It is interpreted alongside your history, examination and, when needed, blood tests.

03 / Why it’s used

Why look at your fingernails?

Capillaries are the body’s smallest blood vessels. At the nailfold — the skin at the base of the nail — they can be seen through the skin with a special microscope. That is why the test is called nailfold capillaroscopy.

Small vessels. A closer look.

Simplified illustration · not to scale

Investigate Raynaud’s

Fingers that change colour with cold or stress may have Raynaud’s phenomenon. Capillaroscopy helps assess whether it occurs on its own or alongside another condition.

Look for useful clues

Some capillary changes can point towards a connective tissue disease, especially systemic sclerosis (a form of scleroderma). They are one part of the assessment.

Follow changes over time

When appropriate, a specialist can compare examinations over time alongside symptoms and other tests.

A common question

I have Raynaud’s: why have I been referred for capillaroscopy?

A plain-language guide to the test and what the results can mean.

04 / Your appointment

What happens during the test?

The test does not hurt and is non-invasive. You sit with your hands supported while a clinician looks at the skin beside your nails. There are no needles, cuts or skin samples.

Simplified drawing of a gloved hand holding an illuminated microscope against the skin beside a fingernail’s cuticle — Illustration of the illuminated lens resting gently on the skin at the base of the nail.

Settle in
Rest in a comfortably warm room so your hands can adjust to the temperature.
A drop of oil
A little oil on the nailfold helps make the vessels easier to see.
A closer look
A microscope or camera examines several fingers and records images.
Back to your day
The oil is wiped away. The test itself usually needs no recovery time.

Before you go

Follow your clinic’s instructions about nail polish or artificial nails. Avoid cutting or pushing back your cuticles beforehand: small injuries can affect the images. Ask the clinic about any preparation you are unsure of.

The test often takes around 20 minutes; allow extra time for preparation and warming your hands. Your clinic can confirm the appointment length.

05 / Common questions

A few common questions

The essentials, without the technical detail.

Does capillaroscopy hurt?

No, capillaroscopy does not hurt. It is a painless, non-invasive examination: the microscope looks at the blood vessels through the skin, without needles, cuts or injections.

Is it a blood test?

No. Capillaroscopy takes images of small blood vessels through the skin. A blood test may be requested separately as part of your assessment.

Does everyone with cold hands need this test?

No. Cold hands alone do not determine whether capillaroscopy is needed. A doctor considers your symptoms and examination before deciding if it would help.

Can I understand my results by comparing pictures?

Pictures can help you learn what the test shows, but cannot establish your diagnosis. The quality of the images, findings across several fingers and your medical history all matter.

What is videocapillaroscopy?

It is capillaroscopy using a camera that displays magnified images on a screen. The images can be saved for measurement and comparison at later visits.

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