How much does Epanutin (Phenytoin) cost at Wimpole Street?

£75 — the standard price that applies to everyone. There is no discounted members’ tier at Wimpole Street and nothing to join. Where a venous draw is needed, a phlebotomy fee is shown on the page before you book and is charged once per visit however many tests are taken.

Should I take my medicine before the blood test?

For most drug levels, no — a trough level is taken just before the next dose. Bring your medicine with you and take it straight after the sample. If you are unsure, do not skip a dose; instead contact the clinic so the timing can be arranged correctly.

Will you adjust my dose based on the result?

No. The laboratory report shows whether the level sits within, above or below the usual range. We do not interpret it — contact your prescriber with the report, since dose changes are made by the clinician responsible for your treatment.

How long do drug level results take?

Common levels such as lithium, digoxin, carbamazepine and phenytoin are typically reported within 24 hours of the sample reaching the laboratory. Immunosuppressant and less common drug assays may take several days, and TPMT or DPD enzyme testing around one to two weeks.

Can drug levels be checked for a child on anti-epileptic medication?

Medical services at Wimpole Street are for patients aged 16 and over. Children’s drug monitoring is arranged through their paediatric team or NHS GP.

Why is my level high when I have not changed my dose?

New medicines, changes in kidney or liver function, dehydration, illness or even dietary changes can alter how a drug is cleared. A high level should be discussed promptly with your prescriber, and if you feel unwell — tremor, confusion, vomiting or palpitations — call NHS 111 or 999 depending on severity.

📍 Wimpole StreetOpening 1 Oct

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Individual Test

Epanutin (Phenytoin) Blood Test Marylebone

From 1 October 2026 — until then book at South Kensington or St Paul's. South Kensington · St Paul's

20 min appointment

Results: 1 day"

Venous blood

£75

+ £50 phlebotomy fee (per visit)

Price

£75

+ £50 phlebotomy (per visit)

Confidential Results

Secure online portal

Fast Results

1 day"

Professional Service

Experienced phlebotomists

Wimpole Street, Marylebone (opening 1 October 2026)

22 Wimpole Street, Marylebone, London W1G 8GQ

020 7183 0692

wimpolestreet@md.co.uk

Opens 1 October 2026

Opening hours from 1 October 2026

Monday: 9am – 6pm
Tuesday: 9am – 8pm
Wednesday: 9am – 6pm
Thursday: 9am – 8pm
Friday: 8am – 5pm
Saturday: 10am – 4pm
Sunday: Closed

Bond Street — about 6 minutes (Central, Jubilee & Elizabeth lines)
Oxford Circus — about 7 minutes (Central, Bakerloo & Victoria lines)

Wimpole Street, Marylebone

Epanutin (Phenytoin) is a therapeutic drug monitoring test concerned with seizure medication level, epilepsy drug test and blood phenytoin concentration, run on a venous blood sample (serum). At Wimpole Street it is priced at £75 for everyone and, from 1 October 2026, a nurse or phlebotomist takes the sample at 22 Wimpole Street, Marylebone. The laboratory quotes 1 day; the report, with reference ranges, is delivered to your secure portal for you to discuss with your GP or a clinician.

therapeutic drug monitoring · Wimpole Street

Epanutin (Phenytoin)’s place in therapeutic drug monitoring testing

Sample: venous blood sample (serum)
Laboratory turnaround: 1 day
Appointment: 20 minutes
Standard price: £75 + £50 phlebotomy per visit

Preparing for your Epanutin (Phenytoin)

1Timing is critical: most levels are “trough” samples taken just before the next dose is due — usually 12 hours after the last dose for twice-daily medicines. Do not take your morning dose until after the blood is drawn unless told otherwise.
2Digoxin is sampled at least six hours after the last dose; lithium 12 hours after; the nurse will confirm timing for your medicine.
3Record the exact time of your last dose and the current dose so the laboratory can interpret the level.
4Do not change your dose because of a result without speaking to the prescriber.

Sample for this test: venous blood sample (serum).

What Epanutin (Phenytoin) measures

Epanutin (Phenytoin) is most often requested in connection with seizure medication level, epilepsy drug test and blood phenytoin concentration, which is why it sits within the therapeutic drug monitoring group at Wimpole Street.

Therapeutic drug monitoring measures the concentration of a medicine in your blood to check that it sits in the range where it works without causing toxicity. It is used for drugs with a narrow margin between effective and harmful doses — anti-epileptics such as carbamazepine, phenytoin, valproate and lamotrigine; lithium; digoxin; immunosuppressants such as tacrolimus and ciclosporin; certain antibiotics including gentamicin and vancomycin; and some antidepressants and antipsychotics. Related enzyme tests such as TPMT and DPD predict how quickly you will clear specific medicines before treatment starts.

Who considers Epanutin (Phenytoin)

People often consider drug level testing if seizures have returned or side effects have appeared after a stable period on medication.
Those on lithium need regular levels, and many prefer to have interval checks that fit around work.
Transplant recipients on tacrolimus or ciclosporin monitor levels closely, especially after any change in dose or other medication.
Someone starting a new medicine that interacts with an existing one may check that the level has not drifted.
A pre-treatment TPMT test is standard before azathioprine, and DPD before certain chemotherapy.

Understanding your Epanutin (Phenytoin) results

A level within the therapeutic range suggests the dose is appropriate, though some people are well controlled below it or need to be above it; the range is a guide, not a target. A level above the range can indicate a risk of toxicity and warrants prompt discussion with the prescriber, particularly for lithium and digoxin. Low levels may reflect missed doses, rapid metabolism or an interaction and should be discussed before any adjustment.

Drug levels are only meaningful when the sample timing relative to the last dose is known, and dose changes are a decision for the prescribing clinician.

Related areas of testing at Wimpole Street: kidney function and electrolytes, liver function, genetic testing, heavy metals and toxicology.

Pricing

Epanutin (Phenytoin)

Individual test

£75

Phlebotomy Fee

Blood draw by qualified phlebotomist (per visit)

£50

Total

£125

Payment is collected at the clinic. The phlebotomy fee is charged once per visit, regardless of the number of tests booked.

How it works at Wimpole Street

From booking the Epanutin (Phenytoin) to reading your result

1
Choose your test
Select the Epanutin (Phenytoin) and any others you want run from the same visit. Until 1 October 2026 the identical test can be booked at South Kensington or St Paul’s.
2
Nurse-led sample
From 1 October 2026 the venous blood sample (serum) is taken at 22 Wimpole Street, Marylebone by our nursing team, led by Precious Agbonmamwen, Registered Adult Nurse (NMC 20H1641E). Identity is checked and any preparation questions answered first.
3
UKAS-accredited laboratory
The sample travels to a UKAS-accredited partner laboratory, whose methods and reference ranges match those used across the NHS and private sectors.
4
Laboratory report to your secure portal
The laboratory report is released to your secure portal — typically from 24 hours; the laboratory quotes 1 day for this test. It shows each value against the reference range and flags anything outside it; discuss the report with your GP or a clinician.

Marylebone, W1

Why test at Wimpole Street

Wimpole Street Medical & Dental opens at 22 Wimpole Street on 1 October 2026. Medical services are for patients aged 16 and over; registration with the CQC is in progress ahead of opening.

Wimpole Street, Marylebone (opening 1 October 2026)

22 Wimpole Street, Marylebone, London W1G 8GQ

020 7183 0692

wimpolestreet@md.co.uk

Opens 1 October 2026

Bond Street — about 6 minutes (Central, Jubilee & Elizabeth lines)
Oxford Circus — about 7 minutes (Central, Bakerloo & Victoria lines)

Bond Street is about six minutes on foot and Oxford Circus about seven, so the clinic suits people working across the West End.
Repeat or additional tests can usually be added to the same visit rather than requiring a second appointment.
One standard price applies to everyone — there is no members’ tier at Wimpole Street.

More therapeutic drug monitoring tests

Other tests often considered alongside Epanutin (Phenytoin)

All blood tests at Wimpole Street

Frequently Asked Questions

A venous blood sample (serum). A nurse or phlebotomist collects it at 22 Wimpole Street, Marylebone from 1 October 2026; the appointment allows time for identity checks and any preparation questions. The laboratory quotes 1 day for this test.

Ready to Book Your Test?

Wimpole Street opens 1 October 2026. Register your interest for the Marylebone diary, or book the same test now at South Kensington or St Paul's.

Important information about the Epanutin (Phenytoin) at Wimpole Street

Medical services at Wimpole Street Medical & Dental are for patients aged 16 and over.
This is a self-referral service: you choose the test and book directly — no GP referral is needed.
Nurse-led by Precious Agbonmamwen, Registered Adult Nurse (NMC 20H1641E), who oversees sample-taking standards, infection control and the patient pathway. The nursing team does not interpret results.
A laboratory result is not a diagnosis and this page is not a substitute for medical advice. We do not provide clinical interpretation of results — please discuss your report with your GP or a clinician, particularly if a value is flagged or you have symptoms.
CQC registration for Wimpole Street is in progress ahead of the opening on 1 October 2026; our South Kensington and St Paul’s clinics are CQC registered.
Your results are held on a secure portal and treated as strictly confidential, except where disclosure is required by law.
If you are seriously unwell, call 999. For urgent advice that is not an emergency, call NHS 111.