Valium (Diazepam) Blood Test Marylebone
From 1 October 2026 — until then book at South Kensington or St Paul's. South Kensington · St Paul's
£125
+ £50 phlebotomy fee (per visit)
+ £50 phlebotomy (per visit)
Confidential Results
Secure online portal
Fast Results
7 days"
Professional Service
Experienced phlebotomists
Wimpole Street, Marylebone (opening 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
Within the therapeutic drug monitoring range at Wimpole Street, the Valium (Diazepam) is the test to consider when the question concerns benzodiazepine, anti-anxiety medication and sedative drug. It costs £125, and once the Marylebone clinic opens on 1 October 2026 a nurse or phlebotomist takes the venous blood sample (EDTA), with the laboratory typically reporting in 7 days. Medical services are for patients aged 16 and over, self-referral with no GP referral needed, and the laboratory report is delivered to your secure portal.
Valium (Diazepam)’s place in therapeutic drug monitoring testing
- Sample
- venous blood sample (EDTA)
- Laboratory turnaround
- 7 days
- Appointment
- 20 minutes
- Standard price
- £125 + £50 phlebotomy per visit
What Valium (Diazepam) measures
Laboratories file the Valium (Diazepam) under benzodiazepine, anti-anxiety medication and sedative drug. The following sections set out how a therapeutic drug monitoring test of this kind is measured and read.
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 Valium (Diazepam)
- 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.
Preparing for your Valium (Diazepam)
- 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 (EDTA).
Understanding your Valium (Diazepam) 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
Valium (Diazepam)
Individual test
Phlebotomy Fee
Blood draw by qualified phlebotomist (per visit)
Total
£175Payment is collected at the clinic. The phlebotomy fee is charged once per visit, regardless of the number of tests booked.
From booking the Valium (Diazepam) to reading your result
- 1
Choose your test
Select the Valium (Diazepam) 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 (EDTA) 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 7 days 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.
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)
- Bond Street — about 6 minutes (Central, Jubilee & Elizabeth lines)
- Oxford Circus — about 7 minutes (Central, Bakerloo & Victoria lines)
- Self-referral: you choose the test and book directly — no GP referral is needed, and the laboratory report is yours to take to your GP or a clinician.
- The same catalogue already runs at South Kensington and St Paul’s, so you can test now and move your records to Marylebone later.
- Analysis is carried out by a UKAS-accredited partner laboratory, so methods and reference ranges match those used across the NHS.
Other tests often considered alongside Valium (Diazepam)
Frequently Asked Questions
A venous blood sample (EDTA). 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 7 days 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 Valium (Diazepam) 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.
