Patient information

Blood tests

Find out what to expect when you come to our clinics for your blood test.

Booking your appointment for a blood test

If you are referred for a blood test by your GP, your GP practice should book your test online for you.

To book an appointment please follow the below links:

Charing Cross Phlebotomy
Hammersmith Phlebotomy
St. Mary's Phlebotomy - this service does not accept GP referrals.
Willesden Community Diagnostic Centre

During your appointment

You will need to wear a face covering throughout your visit to the hospital. Blood tests take place in our phlebotomy department, outpatient reception staff will be happy to direct you.

When you have your blood test there is a very low risk that bruising could occur in conditions which include:

drugs such as warfarin or aspirin
conditions such as a bleeding disorder or low platelets (thrombocytopenia)
when it is hard to get a vein, for example if the arm is swollen

What happens during a blood test?

A test usually involves placing a needle attached to a stylet into one of the blood vessels in the inside of your elbow or the back of your hand. You will feel a sharp scratch as the needle goes in but this isn't particularly painful.

Most blood tests only take a few minutes to complete.

After your appointment

If you were asked to fast before your test, it is possible you will feel light-headed afterwards, so please have a drink and something to eat afterwards.

The time scale for the results varies depending on the type of test. The requesting clinician for the blood test will be able to advise on approximate time scale for the test result.