Osmolality (Urine) Blood Test Marylebone
From 1 October 2026 — until then book at South Kensington or St Paul's. South Kensington · St Paul's
£59
Confidential Results
Secure online portal
Fast Results
1 day"
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
From 1 October 2026 the Osmolality (Urine) can be arranged at Wimpole Street Medical & Dental for £59. A random urine sample is taken by a nurse or phlebotomist and sent to a UKAS-accredited partner laboratory, which quotes 1 day for this kidney function and electrolytes test. The laboratory report shows each value for kidney function and dehydration test against its reference range and is released to your portal; we do not interpret results, so take it to your GP or a clinician.
Osmolality (Urine)’s place in kidney function and electrolytes testing
- Sample
- random urine sample
- Laboratory turnaround
- 1 day
- Appointment
- 20 minutes
- Standard price
- £59
Preparing for your Osmolality (Urine)
- 1No fasting is needed; drink water as normal, since a low fluid intake can push creatinine up.
- 2Avoid a large protein meal or a heavy gym session the day before, since both raise creatinine temporarily.
- 3Creatine supplements can also inflate creatinine; mention them to whoever interprets your report so they can account for it.
Sample for this test: random urine sample.
What Osmolality (Urine) measures
Laboratories file the Osmolality (Urine) under kidney function, dehydration test and urine concentration. The following sections set out how a kidney function and electrolytes test of this kind is measured and read.
Kidney tests measure waste products the kidneys clear — creatinine and urea — and use creatinine, age and sex to estimate filtration rate (eGFR). Electrolytes such as sodium, potassium, chloride and bicarbonate show how well fluid and acid–base balance is being maintained, and cystatin C offers an alternative filtration marker less affected by muscle mass. Urine albumin-to-creatinine ratio, when added, looks for early protein leak.
Who considers Osmolality (Urine)
- People often consider kidney tests if they have high blood pressure or diabetes, both of which place the kidneys under long-term strain.
- Regular use of anti-inflammatory painkillers, lithium or certain blood pressure tablets is a common reason to monitor.
- Swollen ankles, foamy urine or passing water more often at night may prompt a check.
- Those with a family history of polycystic kidney disease or kidney failure frequently want a baseline.
- It is included in most general health screens and before starting some medicines and supplements.
Understanding your Osmolality (Urine) results
A high creatinine or low eGFR can indicate reduced filtration, though a single value in a muscular person or after dehydration may overstate the problem. Potassium and sodium outside their ranges are taken seriously because they affect heart rhythm and fluid balance, and the laboratory may telephone the clinic if a value is markedly abnormal. Trends over time matter more than a single snapshot, so previous results are useful.
eGFR is an estimate derived from creatinine and is less reliable at extremes of body size or in pregnancy; interpretation depends on your history and any medicines.
Related areas of testing at Wimpole Street: liver function, urine tests, diabetes, glucose and HbA1c, bone, calcium and parathyroid.
Pricing
Osmolality (Urine)
Individual test
Total
£59Payment is collected at the clinic. The phlebotomy fee is charged once per visit, regardless of the number of tests booked.
From booking the Osmolality (Urine) to reading your result
- 1
Choose your test
Select the Osmolality (Urine) 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 random urine sample 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.
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)
- Registration with the CQC is in progress ahead of opening; our South Kensington and St Paul’s clinics are CQC registered.
- Samples are taken by a nurse or phlebotomist at 22 Wimpole Street, Marylebone, in a clinic built for medical and dental care.
- 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.
Other tests often considered alongside Osmolality (Urine)
- Uric Acid (Urine)Wimpole Street, Marylebone · from 1 October 2026
- ChlorideWimpole Street, Marylebone · from 1 October 2026
- Electrolytes (Urine)Wimpole Street, Marylebone · from 1 October 2026
- Urate (Uric acid)Wimpole Street, Marylebone · from 1 October 2026
- Xanthine – BloodWimpole Street, Marylebone · from 1 October 2026
- Creatinine (including eGFR) (Venous)Wimpole Street, Marylebone · from 1 October 2026
Frequently Asked Questions
A random urine sample. 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 Osmolality (Urine) 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.
