Dialysis access (fistula) assessment

What is a dialysis access assessment?

If your kidneys are failing, you may need haemodialysis, a treatment that filters your blood through a machine. To do this, the team needs reliable access to your bloodstream that can handle a high flow of blood. The best long-term option for most people is an arteriovenous (AV) fistula: a small operation joins an artery to a vein in your arm, so the vein grows stronger and larger over a few weeks and can be used for dialysis.

The access assessment is the planning step before any operation. A kidney doctor or vascular surgeon reviews your history and examines both arms, and you usually have an ultrasound scan (often called vein mapping). The ultrasound measures the size and health of the arteries and veins in your arms to find the best place to create access, and to check the vessels are big enough and not blocked.

The assessment does not create the access; it decides whether a fistula is possible and where, or whether another option (a graft, or a tube called a line or catheter) is more suitable. Good planning makes a working fistula more likely and helps avoid using temporary lines, which carry more infection risk.

Types, options & approaches

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

Common haemodialysis access options

Your team weighs your vessels, urgency and overall health; a fistula is usually preferred where time and anatomy allow.

Preparing for your test

• Bring details of any previous dialysis lines, cannulas, drips or arm/chest surgery, as these affect which vessels can be used.
• Tell the team which is your dominant (writing) hand, as access is often placed in the non-dominant arm.
• Mention any arm swelling, previous blood clots, pacemaker or heart device.
• Bring a list of your medicines, including blood thinners.
• Wear clothing with sleeves that roll up easily so both arms can be examined and scanned.
• Ask whether you should avoid having blood taken or drips put into the arm being considered, to protect the veins.

What happens

The assessment is done as an outpatient. A kidney doctor or vascular surgeon talks through your kidney condition and dialysis plan, and examines both arms, feeling the pulses and looking at the veins, sometimes with a tourniquet to make the veins stand out.

For the ultrasound (vein mapping), you sit or lie with your arm supported. A sonographer puts gel on your skin and moves a probe over your arm to measure the arteries and veins and check blood flow. It is usually not painful and usually takes about 30 minutes. In some cases extra imaging of the deeper or central veins is arranged on another day.

The team then discusses the findings with you: whether a fistula is possible and where, or whether a graft or line is more appropriate, and what happens next. If a fistula is recommended, a separate operation is planned, ideally well before you need to start dialysis.

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 assessment is safe; the harder reality is what it may find. Veins and arteries that are too small, narrowed or scarred from previous drips and lines can make a fistula less likely to work, and not every fistula matures even when the scan looks favourable. Ask what your scan showed, how likely your planned access is to work, and what the backup plan is.

Published figures to discuss

The assessment is very low risk, so the meaningful numbers are about how often a created fistula actually works. These come from studies of fistula outcomes and vary widely with vessel size, fistula site and patient health; ultrasound planning improves the odds but does not guarantee success.

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 recovery from the assessment itself, which is just a clinic visit and an ultrasound. What follows is a plan for your dialysis access; any recovery relates to a later operation, not this appointment.

• No physical after-effects from the assessment
• A clear plan for your dialysis access
• Sometimes needing a further scan to complete planning
• Understanding that any fistula will need time to mature after a later operation

Aftercare

• Protect the veins in the arm being considered: ask staff not to take blood or place drips there if possible.
• Keep any follow-up appointments for further imaging or to plan surgery.
• Ask what your scan showed and what access is recommended and why.
• Tell the team promptly about new arm swelling, pain or colour change.
• Keep your skin and arms in good condition ahead of any planned surgery.
• Make sure you understand the timeline, including how long a fistula needs to mature.

• Details of all previous lines, cannulas and arm/chest surgery
• Note of your dominant hand
• List of medicines including blood thinners
• Information on any pacemaker, device or previous clots
• Clothing with easy-access sleeves for the appointment
• Questions about which access is best and the timeline

⚠ Get urgent help if…

• New swelling of the arm, hand or face
• Severe arm pain, numbness, coldness or a hand that looks pale or blue
• Signs of infection (redness, heat, swelling, fever) around any existing line or wound
• Bleeding that will not stop from any access site
• A previously buzzing fistula that goes quiet or stops (loss of the thrill), which needs urgent contact
• Feeling generally unwell with fever if you already have a dialysis line

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 favourable assessment means suitable vessels have been found and a fistula (or other access) can be planned with a reasonable chance of working. A less favourable result means the team will consider a different site, a graft or a line, and may arrange more imaging.

The assessment plans access; it cannot guarantee the access will work. Even with good vessels, some fistulas fail to mature or need a further procedure to help them along. The scan describes your vessels at one point in time and guides the safest plan, but the outcome also depends on the surgery, healing and your overall health.

A working fistula can last for years and is generally the most durable access, but it needs ongoing care and monitoring, and any access can narrow or clot over time. Veins can change, so the assessment reflects the situation now; if circumstances change, the plan may need revisiting.

Related tests, treatments or support

Access assessment is part of wider planning for kidney failure, alongside discussion of dialysis options (haemodialysis or peritoneal dialysis), transplant assessment where appropriate, and management of blood pressure, anaemia and bone health by the kidney team.

Follow-up & long-term care

If a fistula or graft is recommended, you will be referred for surgery and reviewed afterwards to check it is maturing. If a line is needed first, the team plans how and when to move to a longer-term access. You will be told who to contact about your access.

• Protecting the planned access arm from unnecessary needles, drips and tight cuffs
• Regular checks of a fistula or graft once created (feeling for the buzz/thrill)
• Keeping the access area clean and reporting any redness, swelling or pain
• Ongoing monitoring by the dialysis access team for narrowing or clotting
• Keeping appointments for surveillance scans if advised

Repeat, follow-on and what comes next

• Some fistulas need a further procedure (such as angioplasty or a small operation) to help them mature or to fix narrowing.
• If a fistula fails, another site, a graft or a line may be needed.
• Access often needs ongoing surveillance and occasional intervention to keep it working.
• A temporary line may be required while a fistula matures.

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 access plan with a named contact in the dialysis access team.
• Advice on protecting the access arm and recognising problems early.
• Planned surveillance of any fistula or graft for narrowing or clotting.
• A realistic timeline and backup plan discussed openly.

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:

• Specialist consultation with a kidney doctor or vascular surgeon
• The vein mapping ultrasound and who performs and reports it
• Any additional imaging such as a venogram or CT of the central veins
• Follow-up appointments to plan surgery and review maturation
• Complexity of your vessels and whether previous lines have caused narrowing
• The access option chosen and its later surgical costs (assessed separately)

• The consultation fee and who carries out the assessment
• Whether the vein mapping ultrasound and its reporting are included
• The cost of any additional imaging if the veins are unclear
• Whether follow-up to plan surgery is included
• What happens, and what it costs, if further investigation is needed
• How the later access operation and its follow-up are charged

On the NHS? Dialysis access assessment and planning are normally provided on the NHS by a renal and vascular access team; private care exists but this is usually part of NHS kidney services.

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.

• What did my vein mapping show, and which access do you recommend and why?
• How likely is my planned fistula to work, and what is the backup plan?
• Which arm will be used, and how should I protect those veins now?
• How long before I need dialysis should the access be created?
• What are the pros and cons of a fistula, graft or line for me?
• Who do I contact if I notice swelling, pain or changes in the access arm?
• 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 dialysis access (fistula) assessment

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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: Kidney Care UK — Haemodialysis (access and fistula) Pre-operative ultrasound mapping before AV fistula formation (meta-analysis) — PMC Routine preoperative vascular ultrasound improves fistula outcomes (RCT) — PMC Current role of ultrasound in haemodialysis access evaluation — PMC Arteriovenous fistula maturation failure in a large cohort — PMC NICE NG107 — Renal replacement therapy and conservative management (2018) UK Kidney Association — Clinical Practice Guideline: Vascular access for haemodialysis (2025)

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.